Range Field Day 2008 Progress Report

Transcription

1 Specil Report 185 June 28 Rnge Field Dy 28 Progress Report United Sttes Deprtment of Agriculture Agriculturl Reserch Service

2 For dditionl copies of this puliction Estern Oregon Agriculturl Reserch Center (EOARC) A Hwy 25 Burns OR Deprtment of Rngelnd Ecology nd Mngement Strnd Agriculturl Hll Oregon Stte University Corvllis OR A PDF of the puliction will e ccessile from the EOARC wesite t

3 Agriculturl Experiment Sttion Oregon Stte University Specil Report 185 June 28 Rnge Field Dy 28 Progress Report Estern Oregon Agriculturl Reserch Center Deprtment of Rnge Ecology nd Mngement Oregon Stte University Agriculturl Reserch Service, U.S. Deprtment of Agriculture This report is coopertive effort of the Deprtment of Rngelnd Ecology nd Mngement, Oregon Stte University, nd the Estern Oregon Agriculturl Reserch Center. Any mention of commercil products does not constitute endorsement y Oregon Stte University or the USDA-Agriculturl Reserch Service. The Estern Oregon Agriculturl Reserch Center, which includes Burns nd Union Sttions, is jointly operted nd finnced y the U.S. Deprtment of Agriculture-Agriculturl Reserch Service, Oregon Stte University, nd the Oregon Agriculturl Experiment Sttion. Acknowledgments Mny privte lndowners, stte, nd federl gencies hve provided funds nd/or use of lnds to perform the reserch presented in this report. We wish to thnk the following privte lnd owners for their contriutions; Tim nd Bill Lowery, Mike Stnford, Fred nd Deie Otley, Lrry nd Sue Otley, the Mullin Rnch, nd the Lm Rnch. Federl lnd mngement gencies to e recognized re the Burns, Lkeview, Alturs, Prineville, nd Owyhee field offices of the USDI-Bureu of Lnd Mngement. Other federl support hs een received from U.S. Deprtment of Agriculture-Agriculturl Reserch Service nd the Joint Fire Science Progrm. Stte support hs een provided y the Oregon Agriculturl Experiment Sttion nd Idho Deprtment of Lnds. We wish to thnk Georjnn Pokorney, Slly Olson-Edge, nd Ariel Ginsurg for editing nd preprtion of this report. Trde-nme products nd services re mentioned s illustrtions only. This does not men tht the Oregon Stte University Agriculturl Experiment Sttion either endorses these products nd services or intends to discriminte ginst products nd services not mentioned.

4 TABLE OF CONTENTS Forwrd Grzing Mngement Influence of long-term livestock grzing exclusion on the response of sgerush-steppe plnt communities to fire. Kirk Dvies, Tony Svejcr, nd Jon Btes Grzing fter fire in the sgerush-steppe. Jon Btes, Ed Rhodes, Kirk Dvies nd Ro Shrp Defolition impcts on ove nd elow-ground production in riprin sedge community Chd Boyd nd Tony Svejcr Do grzing cttle seek nutritionlly superior portions of psture? Dve Gnskopp nd Dvid Bohnert Medushed Ecology nd Mngement Medushed estlishment nd dispersl in sgerush-unchgrss communities Kirk Dvies Medushed outperforms squirreltil. Jne Mngold nd Kert Young Effects of imzpic on trget nd nontrget vegettion during revegettion. Roger Sheley, Mike Crpinelli, Kimerly J. Reever-Morghn, nd Edwrd Vsquez Crested whetgrss defolition intensity nd seson of use on medushed invsion. Roger Sheley, Brett Binghm, nd Tony Svejcr, nd Edwrd Vsquez Western Juniper Ecology nd Mngement A history of woodlnd dynmics in the Owyhee s: encrochment, stnd closure, understory dynmics, nd tree iomss. Rick Miller, Jmie Rtchford, nd Dustin Johnson Juniper cutting nd prescried fire comintions; South Mountin, Idho. Jon Btes, Kirk Dvies, Roger Sheley, nd Ro Shrp Hydrologic response to western juniper control. Tim DeBoodt, Michel Fisher, John Buckhouse, nd John Swnson Runoff nd erosion fter cutting western juniper. Fred Pierson, Jon Btes, Tony Svejcr, nd Sturt Hrdegree

5 Restortion of quking spen woodlnds invded y western juniper. Jon Btes, Rick Miller, nd Kirk Dvies A generlized model for estimting iomss nd fuel lods for western juniper. Jime Rtchford, Brenn Sin, Andrew Tierney, Rick Miller, nd Pul Doescher AUTHORS JON BATES, Rngelnd Scientist, Estern Oregon Agriculturl Reserch Center, USDA- Agriculturl Reserch Service, Burns, Oregon BRETT BINGHAM, Rnge Technicin, Estern Oregon Agriculturl Reserch Center, USDA-Agriculturl Reserch Service, Burns, Oregon DAVID BOHNERT, Rnge Animl Nutritionist, Estern Oregon Agriculturl Reserch Center, Oregon Stte University, Burns, Oregon CHAD BOYD, Rngelnd Scientist, Estern Oregon Agriculturl Reserch Center, USDA- Agriculturl Reserch Service, Burns, Oregon JOHN BUCKHOUSE, Extension Wtershed Specilist/Professor, Oregon Stte University Deprtment of Rngelnd Ecology nd Mngement, Corvllis, Oregon MICHAEL CARPINELLI, Ntionl Resource Conservtion Service, Aluquerque, New Mexico KIRK DAVIES, Rngelnd Scientist, Estern Oregon Agriculturl Reserch Center, USDA-Agriculturl Reserch Service, Burns, Oregon TIM DEBOODT, County Extension Agent/Associte Professor, Oregon Stte University Extension Service, Crook County, Prineville, Oregon PAUL DOESCHER, Professor, Oregon Stte University, Deprtment of Forest Science, Corvllis, Oregon MICHEAL FISHER, Associte Professor, Forestry Deprtment, Centrl Oregon Community College, Bend, Oregon DAVE GANSKOPP, Rngelnd Scientist, Estern Oregon Agriculturl Reserch Center, USDA-Agriculturl Reserch Service, Burns, Oregon STUART HARDEGREE, Plnt Physiologist, Northwest Wtershed Reserch Center, USDA-Agriculturl Reserch Service, Boise, Idho

6 DUSTIN JOHNSON, Rnge Extension, Hrney County, Oregon Stte University, Burns, Oregon JANE MANGOLD, Rngelnd Scientist, Estern Oregon Agriculturl Reserch Center, USDA-Agriculturl Reserch Service, Burns, Oregon RICK MILLER, Professor Rngelnd Ecology, Estern Oregon Agriculturl Reserch Center, Oregon Stte University, Burns, Oregon FRED PIERSON, Reserch Leder, Northwest Wtershed Reserch Center, USDA- Agriculturl Reserch Service, Boise, Idho JAIME RATCHFORD, Reserch Assistnt, Oregon Stte University Deprtment of Rngelnd Ecology nd Mngement Resources, Corvllis, Oregon KIMBERLY REEVER-MORGHAN, Eugene, Oregon ED RHODES, Reserch Associte, Center for Nturl Resource Informtion Technology, Deprtment of Ecosystem Science nd Mngement, Texs A&M University, College Sttion BREANNA SABIN, Grdute Student, Oregon Stte University, Deprtment of Rngelnd Ecology nd Mngement, Corvllis, Oregon ROB SHARP, Rngelnd Specilist, Bureu of Lnd Mngement, Burns District, Oregon ROGER SHELLY, Weed Ecologist, Estern Oregon Agriculturl Reserch Center, USDA- Agriculturl Reserch Service, Burns, Oregon JOHN SWANSON, Rngelnd Specilist, Bureu of Lnd Mngement, Prineville District, Prineville, Oregon TONY SVEJCAR, Reserch Leder nd Rngelnd Scientist, Estern Oregon Agriculturl Reserch Center, USDA-Agriculturl Reserch Service, Burns, Oregon ANDREW TIERNEY, Grdute Student, Oregon Stte University, Deprtment of Rngelnd Ecology nd Mngement, Corvllis, Oregon EDWARD VASQUEZ, Post-doctorl Reserch Assistnt, USDA-Agriculturl Reserch Service, Burns, Oregon

7 Forwrd The 28 Rnge Field Dy will focus on severl sujects importnt to mnging the Intermountin regions rngelnds productively nd ecologiclly. The min topics presented re livestock grzing mngement, medushed ecology nd mngement, nd western juniper ecology nd mngement. Reserch on the mngement of livestock grzing in western rngelnds continues to dvnce prctices tht properly utilize forge resources while mintining or improving ecosystem vlues. This report ddresses severl grzing issues: fire nd grzing interctions, resilience of riprin communities to defolition, nd developing etter understnding of fctors influencing grzing ptterns nd sesonl movement of cttle in lrge pstures. Medushed, long with chetgrss, re the most pressing mngement issues concerning the helth of sgerush grsslnds. Integrtive mngement tht comines hericide ppliction, fire, nd the reseeding of competitive plnt species ppers to e the most vile pproch to revegette medushed infested rngelnds, leit n expensive tretment. Aggressive nd comprehensive prevention progrms tht include erly detection nd erdiction of medushed remin the est mens for conserving rngelnds tht re currently medushed-free. This report highlights the impcts of severl medushed control pplictions s well s explining why it is such difficult nd chllenging weed to mnge in Intermountin rngelnds. Western juniper remins significnt issue in the mngement of northern Gret Bsin rngelnds. Much progress hs een mde in explining the expnsion of western juniper woodlnds the pst century, quntifying the impcts of woodlnd expnsion on the ecosystem, nd developing mngement tools to control juniper nd restore Gret Bsin plnt communities. Included in the report re evlutions on the mgnitude of juniper expnsion t regionl level, wtershed impcts of woodlnds, nd severl new pproches to juniper control using prtil cutting nd fire comintions to restore sgerush grsslnd nd spen woodlnd. If you hve further questions on the topics of tody s field dy we encourge you to contct the uthors for further informtion. Finlly, most of the projects presented t the Field Dy nd/or in the progress report hve resulted from our interctions with privte nd pulic lnd-owners. The gols of our progrms re to develop nswers nd strtegies tht mintin or enhnce the mny resources nd services provided y our rngelnds. Your input hs nd will continue to e key component for developing reserch progrms tht re pertinent to your interests nd concerns. 1

8 Grzing Mngement 2

9 Influence of Long-term Livestock Grzing Exclusion on the Response of Sgerush Steppe Plnt Communities to Fire Kirk W. Dvies, Tony J. Svejcr, nd Jon D. Btes SUMMARY Livestock grzing of sgerush steppe plnt communities hs een considered to hve negtive impcts ecuse these communities did not evolve with lrge herivores. The est mngement of these ecosystems hs een ssumed to e ccomplished y mimicking historic conditions, such s ppliction of prescried fire. However, the introduction of invsive plnts or ltered environmentl conditions hs potentilly chnged the response of plnt communities to fire disturnce. This study evluted the effects of fire to plnt community dynmics etween grzed psture nd long-term grzing exclosures. Tretments were ungrzed (grzing excluded since 1936), ungrzed urned, grzed unurned, nd grzed urned. Vegettion cover, density, nd iomss production were mesured in the 12 th, 13 th, nd 14 th yer post-urning. Long-term grzing exclusion followed y urning resulted in sustntil chetgrss invsion. The ungrzed urned tretment hd the lest perennil vegettion nd gretest nnul vegettion. The grzed urned tretment hd the gretest mount of perennil herceous productivity nd density mong ll tretments. Our results suggest tht long-term grzing exclusion wekens the ility of Wyoming ig sgerush plnt communities to tolerte fire nd thus llows chetgrss invsion. Low to moderte grzing y domestic livestock ppers to e etter mngement thn grzing exclusion for mintining sgerush steppe. INTRODUCTION & OBJECTIVES Historic disturnce regimes re often reconstructed to direct ecosystem mngement. It hs een ssumed tht the est mngement nd restortion of ecosystems would e ccomplished y mimicking historic disturnce regimes. However, some environmentl conditions nd iotic potentils hve een irreversily ltered nd, therefore, could potentilly chnge the response of the plnt community to disturnce. For exmple, climte chnge or invsive plnts could result in different response to disturnce thn expected. Thus, the outcome of reintroducing historic disturnces in ntive plnt communities is not well understood, especilly with the thret of invsive plnts. To evlute reintroducing historic disturnces, we investigted the implictions of reintroducing fire with nd without long-term livestock grzing in Wyoming ig sgerush plnt communities in the northern Gret Bsin. Wyoming ig sgerush plnt communities hve een estimted to hve historic fire return intervl of 5-1 yers nd evolved with few lrge herivores resulting in little grzing pressure. 3

10 The impcts of livestock grzing on plnt communities tht did not evolve with lrge numers of herivores re generlly considered negtive. These plnt communities re expected to e intolernt of livestock grzing pressure. However, light to moderte utiliztion y domestic livestock hs een demonstrted to hve miniml impcts on sgerush plnt communities. Understnding the impcts of different disturnces ptterns on Wyoming ig sgerush plnt communities is importnt ecuse most of these communities re grzed y domestic livestock, re t risk of urning, nd provide vlule hitt for wildlife. Ungrzed plnt communities re proly more likely to urn ecuse of uildup of fine fuels. If Wyoming ig sgerush communities re going to e mnged ccording to their historic disturnce regime, some lte serl sgerush plnt communities would e prescrie urned nd domestic livestock would e removed. The impct of returning the historic disturnce regime to Wyoming ig sgerush steppe remins uncertin with the current thret of chetgrss invsion. METHODS The study ws conducted t the Northern Gret Bsin Experimentl Rnge (NGBER) in southestern Oregon out 35 miles west of Burns, Oregon, USA. Tretments were: 1) ungrzed unurned, 2) ungrzed urned, 3) grzed unurned, nd 4) grzed urned. Ungrzed tretments were estlished in 1936 with the erection of 5 cre grzing exclosures. Dt collected in 1937 reveled no differences in the densities of Snderg luegrss, lrge perennil grsses, nnul grsses, perennil fors, nd nnul fors etween inside nd outside the exclosures. Chetgrss ws not present inside or outside the exclosures in Ares djcent to the exclosures were grzed y cttle until 199. Grzing pressure ws low to moderte. In lte Septemer of 1993, prescried urning tretments were pplied s striphed fires using drip torches. Vegettion cover, density, nd iomss production were smpled in 25, 26, nd 27, the 12 th, 13 th, nd 14 th yer post-urning, respectively. RESULTS Cover The interction etween urning nd grzing tretments influenced cover of ll herceous functionl groups (Fig.1). Lrge perennil unchgrss cover ws gretest in the grzed urned tretment nd lowest in the ungrzed urned tretment. Chetgrss cover ws 8.6 times greter in the ungrzed urned tretment thn ny of the other tretments. Similrly, nnul for cover ws gretest in the ungrzed urned tretment, while perennil for cover ws lowest in this tretment. Moss cover ws lowest in the ungrzed urned tretment nd highest in the ungrzed unurned tretment. 4

11 14 c Cover (%) c d POSA PG BRTE PF AF Functionl Group Grzed Burned Ungrzed Burned Grzed Unurned Ungrzed Unurned c d c d Figure 1. Functionl group cover (men + S.E.) of the tretments verged over 25, 26, nd 27 t the Northern Gret Bsin Experimentl Rnge. POSA = Snderg luegrss, PG = tll perennil unchgrss, BRTE = chetgrss, PF = perennil for, nd AF = nnul for. Ungrzed = livestock excluded since 1937, Grzed = livestock were llowed to grze until 199, Burned = prescried fll urning in 1993, nd Unurned = no prescried urning. Different lowercse letters indicted significnt difference (P <.5) mong tretments. Density Lrge perennil unchgrss density ws lowest in the ungrzed urned tretment nd highest in the grzed urned tretment with n pproximtely 1.9-fold difference etween the two tretments (Fig. 2). Burning decresed perennil unchgrss density in the ungrzed tretment, ut did not influence unchgrss density in the grzed tretment. Burning incresed chetgrss density in the ungrzed tretment. Perennil for density ws decresed y urning, ut ws not influenced y grzing. Burning generlly incresed green ritrush density, however, the increse in density ws lrgest in the ungrzed tretment. 5

12 Grzed Burned Ungrzed Burned Grzed Unurned Ungrzed Unurned Density (individuls. 11 ft -2 ) c 1 5 c c POSA PG BRTE PF AF Functionl Group Figure 2. Functionl group density (men + S.E.) of the tretments verged over 25, 26, nd 27 t the Northern Gret Bsin Experimentl Rnge. POSA = Snderg luegrss, PG = tll perennil unchgrss, BRTE = Chetgrss, PF = perennil for, nd AF = nnul for. Ungrzed = livestock excluded since 1937, Grzed = livestock were llowed to grze until 199, Burned = prescried fll urning in 1993, nd Unurned = no prescried urning. Different lowercse letters indicted significnt difference (P <.5) mong tretments. Biomss Lrge perennil unchgrss production generlly incresed with urning (Fig. 3). Bunchgrss production incresed more with urning in the grzed compred to the ungrzed tretment. Burning the grzed tretment incresed perennil unchgrss production 1.6-fold. Chetgrss iomss production incresed more thn 49-fold fter urning the ungrzed tretment. Perennil for iomss production decresed 3-fold when the ungrzed tretment ws urned. Biomss production of nnul fors incresed with urning. Annul for production ws lowest in the ungrzed unurned tretment nd highest in the ungrzed urned tretment. In the ungrzed urned tretment, chetgrss produced more iomss thn ll the perennil herceous vegettion comined. Comining chetgrss nd nnul for production revels tht nnuls produced 2.8-fold more iomss thn perennil herceous vegettion in the ungrzed urned tretment. The ungrzed urned tretment ws the only tretment to produce more nnul thn perennil herceous vegettion iomss. 6

13 3 d Grzed Burned Ungrzed Burned Grzed Unurned Ungrzed Unurned Biomss Production (ls. c -1 ) c d c POSA PG BRTE PF AF Functionl Group Figure 3. Functionl group iomss production (men + S.E.) of the tretments verged over 25, 26, nd 27 t the Northern Gret Bsin Experimentl Rnge. POSA = Snderg luegrss, PG = tll perennil unchgrss, BRTE = Chetgrss, PF = perennil for, nd AF = nnul for. Ungrzed = livestock excluded since 1937, Grzed = livestock were llowed to grze until 199, Burned = prescried fll urning in 1993, nd Unurned = no prescried urning. Different lowercse letters indicted significnt difference (P <.5) mong tretments. MANAGEMENT IMPLICATIONS The lck of livestock grzing in the ig sgerush plnt communities wekened the ility of the perennil herceous vegettion to tolerte fire. This could e the result of ccumultion of fuels or loss of mechnisms importnt to tolerting disturnces. Low to moderte livestock grzing ppers to e eneficil to the long-term sustinility of Wyoming ig sgerush plnt communities. Preventing grzing to protect sgerush plnt communities nd sgerush oligte wildlife species my ctully result in their loss. The lrge increse in chetgrss with grzing protection followed y fire is concern. On lrger re, the increse in chetgrss would gretly increse the likelihood of higher fire frequency due to more fine fuel lods nd continuity. The incresed fire frequency would e detrimentl to ntive vegettion nd sgerush oligte wildlife species. 7

14 REFERENCES Bker, W.L Restortion of lndscpe structure ltered y fire suppression. Conservtion Biology 8: Belsky, A.J., nd D.M. Blumenthl Effects of livestock grzing on stnd dynmics nd soils in uplnd forests of the Interior West. Conservtion Biology 11: Courtois, D.R., B.L. Perrymn, nd H.S. Hussein. 24. Vegettion chnge fter 65 yers of grzing nd grzing exclusion. Journl of Rnge Mngement 57: Dvies, K.W., J.D. Btes, nd R.F. Miller. 27. Short-term effects of urning Wyoming ig sgerush steppe in southest Oregon. Rngelnd Ecology nd Mngement 6: Eckert, R.E., nd J.S. Spencer Vegettion response on llotments grzed under restrottion mngement. Journl of Rnge Mngement 39: Eckert, R.E., nd J.S. Spencer Growth nd reproduction of grsses hevily grzed under rest-rottion mngement. Journl of Rnge Mngement 4: Fleischner, T.L Ecologicl costs of livestock grzing in western North Americ. Conservtion Biology 8: Mck, R.N., nd J.N. Thompson Evolution in steppe with few lrge, hooved mmmls. The Americn Nturlist 119: Mnier, D.J., nd N.T. Hos. 26. Lrge herivores influence the composition nd diversity of shru-steppe communities in the Rocky Mountins, USA. Oecologi 146: Rice, B., nd M. Westoy Vegettive responses of some Gret Bsin shru communities protected ginst jckrits or domestic stock. Journl of Rnge Mngement 31: Rickrd, W.H Experimentl cttle grzing in reltively undistured shrusteppe community. Northwest Science 59: West, N.E., F.D. Provenz, P.S. Johnson, nd M.K. Owens Vegettion chnge fter 13 yers of livestock grzing exclusion on sgerush semidesert in west centrl Uth. Journl of Rnge Mngement 37: Wright, H.A., nd A.W. Biley Fire Ecology: United Sttes nd Southern Cnd. John Wiley & Sons Inc. New York, NY, USA. pp

15 Grzing After Fire in the Sgerush-Steppe Jon Btes, Ed Rhodes, Kirk Dvies, nd Ro Shrp SUMMARY This study evluted cttle grzing impcts over four growing sesons fter prescried fire on Wyoming ig sgerush steppe in estern Oregon. Tretments included no grzing on urned nd unurned sgerush steppe, two summer grzing pplictions fter fire, nd two spring grzing pplictions fter fire. Tretment plots were urned in fll 22. Grzing ws pplied in Vegettion responses to tretments were evluted y quntifying plnt cover, density, stnding crop, production, nd mesuring perennil grss seed production. Stnding crop nd seed production were greter in the ungrzed urn tretment thn ll grzed urn tretments; however, these differences did not ffect community recovery fter fire. Herceous response vriles (cover, density, nd production), re ground, nd litter cover did not differ mong grzed nd ungrzed urn tretments. Burn tretments (grzed nd ungrzed) hd greter herceous cover, stnding crop, herceous production, nd seed production thn the unurned tretment y the second or third yer fter fire. The results demonstrted tht properly pplied livestock grzing fter low severity fire will not slow or reduce the recovery of plnt communities in ig sgerush steppe. INTRODUCTION In sgerush rngelnds of the western United Sttes, fire hs een nturl nd prescried disturnce temporrily shifting vegettion from shru-grss co-dominnce to grss dominnce. There is limited informtion on the impcts of grzing to community dynmics following fire in the sgerush ecosystem. In 21, we developed study to evlute post-fire herceous recovery of sgerush steppe in estern Oregon s influenced y time of grzing reintroduction. Four moderte grzing tretments fter fire were compred to urned nd unurned tretments in Wyoming ig sgerush steppe. Grzing tretments were comprised of two summer nd two spring scenrios. We predicted tht (1) grzing in the spring strting the second yer fter fire (one yer of rest) would reduce herceous plnt recovery compred to other grzed nd no-grze urn tretments; (2) summer grzing tretments nd spring grzing (with two yers of post-fire rest) would hve similr herceous recovery levels compred to the no-grze urn tretment; nd 3) herceous response in the summer grzing tretments, spring grzing (with two yers postfire rest) tretment, nd the no-grze urn tretment would exceed the unurned tretment within three yers following fire. METHODS The study ws conducted t the Northern Gret Bsin Experimentl Rnge, 35 miles west of Burns, Oregon, USA. Elevtion t the site is 4,5 ft nd slope less thn 2%. Annul precipittion hs verged 11.9 inches since the 193 s. Wyoming ig sgerush ws the dominnt shru nd green ritrush ws secondry shru. The understory ws co-dominted y Idho fescue nd Thurer s needlegrss. Snderg s luegrss, lueunch 9

16 whetgrss, pririe Junegrss, nd ottlerush squirreltil were present s sudominnt grsses. Prescried urning ws pplied in lte Septemer nd erly Octoer, 22. Fires were complete cross urn plots, killing nerly 99% of the Wyoming sgerush present. Cttle grzing impcts to post-fire recovery of herceous vegettion ws evluted over four growing sesons. Thirty cre plots were estlished in 21. There were six tretments pplied nd ll tretments were replicted 5 times. The tretments were; SUMMER 1: grze the first 2 yers fter fire in erly August 23 nd 24. SUMMER 2: grze the second nd third summer fter fire in August 24 nd 25. SPRING 1: grze the second nd third spring fter fire in My 24 nd 25. SPRING 2: grze the third spring fter fire in My 25. This tretment is equivlent to mny post-fire grzing progrms in the region. BURN: no grzing fter fire. UNBURNED: no fire nd no grzing. The summer grzing tretments took plce in erly August when herceous plnts were lrgely dormnt or hd completed tht yer s growth cycle. The spring grzing tretments took plce in erly to mid-my during vegettive nd erly oot stges of growth of the min unchgrss species (Idho fescue, nd Thurer s needlegrss). No grzing ws pplied in 26 s this ws the min response yer we used to compre herceous recovery mong the tretments. Tretment plots were individully fenced to control livestock. Grzing ws mnged to remove 4-5% of herceous stnding crop in ll grzed tretments. This is considered moderte to slightly higher thn moderte level of use in the sgerush steppe. Vegettion responses to tretments were evluted y quntifying plnt cover, density, clipping for stnding crop nd production; nd perennil grss seed production. RESULTS Fire Severity; Fire initilly cused reduction in cover of herceous perennils nd green ritrush. However, densities of herceous perennils nd green ritrush were unffected y the fire indicting fire of low severity. Sgerush ws severely ffected y fire s most individuls were killed. Fire intensity ws sufficient to reduce sgerush to stumps less thn 4 inches in height. Utiliztion; Utiliztion in oth summer grzing tretments nd the SPRING 1 tretment in 24 were close to the trgeted level of 5%. In spring 25, herge ws growing rpidly nd grzed plnts were re-grew quickly while livestock were still grzing in the tretment plots. Mesured utiliztion showed only light use (25%) in SPRING 1 nd SPRING 2 tretments in 25. Bre Ground; Bre ground incresed the first yer fter fire in ll tretments tht were urned (Fig. 1). Bre ground ws greter fter fire in urn tretments (grzed nd ungrzed) thn the UNBURNED in 23. By the second yer fter fire (24) there were no longer ny differences mong tretments nd in the urned tretments levels of re ground did not differ from pre-urn conditions. 1

17 Cover (%) A. Herceous BURN UNBURNED SUMMER 1 SUMMER 2 SPRING 1 SPRING 2,,,,,,,, 1 Cover (%) Cover (%) Cover (%) B. 21 Moss nd Crust c 25 26,,,,,,,,,,,,,,, C 21. Litter c Yer,,,,,,,,,,, D. 21 Bre ground ,,,, Burn, Fll Yer Figure 1. Ground cover vlues for the vrious urn nd grzing tretments in Wyoming ig sgerush steppe, 21-26; A) herceous, B) litter, C) moss nd iotic crust, nd D) re ground nd rock.. Vlues represent mens + one stndrd error. Different lower-cse letters indicte significnt differences (p<.5) mong the tretments within yer. 11

18 Litter; Litter ws reduced y urning nd litter cover ws greter in the UNBURNED tretment compred to most of the urned grzed tretments the first three yers fter fire. (Fig. 1). By 26 tretments did not differ in litter cover. Moss nd Biotic Crust; Moss nd other iotic crust incresed in the UNBURNED tretment etween 22 nd 23 nd remined times greter thn the urned tretments (grzed nd ungrzed) (Fig. 1). Moss comprised most of the cover in this group nd ws minly found within grss clumps nd under sgerush. At this point fire, not grzing, negtively impcted moss nd iotic crust. Herceous Cover; Prior to urning, cover vlues did not differ mong tretments. The first yer fter urning (23) cover ws greter in the UNBURNED thn ll urned tretments (grzed nd ungrzed) for most response vriles (Fig. 1). By the third growing seson (25) fter fire herceous cover ws twice s gret in the urned tretments (grzed nd ungrzed) thn the UNBURNED. Cover remined greter in ll urned tretments thn the UNBURNED tretment in 26, lthough the mgnitude of difference ws only out 2%. In ll tretments, perennil grss cover ws greter thn pre-urn levels in 25 nd 26 ut did not differ mong tretments. Annul for cover ws greter in urned (grzed nd ungrzed) tretments from the second through fourth yer fter fire (24-26). Chetgrss cover remined low (<.1%) throughout the study on ll tretments. Perennil Plnt Density nd Species Presence; Perennil plnt densities remined lrgely unffected y tretment. Fire cused no mesurle mortlity to perennil unchgrsses. There were no differences mong tretments in the numers of species. Numers of herceous species incresed in ll tretments in 25 nd 26 when precipittion ws greter thn verge. Herceous Stnding Crop; Herceous nd functionl group stnding crop did not differ mong tretments prior to urning (Figs. 2 nd 3). By the third (25) nd fourth (26) growing seson fter fire herceous nd perennil grss stnding crop ws greter in ll the urned tretments (grzed nd no-grze) thn the UNBURNED tretment. Stnding crop in the BURN tretment ws out twice s gret s the UNBURNED tretment nd ws greter thn ll the urned-grzed tretments (except the SUMMER 2 tretment) in 25 nd 26. The lower mount of stnding crop in the urn-grzed tretments thn the BURN tretment in 25 nd 26 reflects the removl of herge y livestock tht reduces the mount of crry over iomss from previous yer s growth. Snderg s luegrss stnding crop ws reduced in ll urn tretments fter fire. In 25, Snderg s luegrss stnding crop ws lowest in the SPRING 1 nd SPRING 2 tretments, respectively, thn other tretments. Perennil for stnding crop/production ws reduced in ll urn (grzed nd ungrzed) tretments the first yer fter fire. Annul for stnding crop/production incresed in ll urn tretments (grzed nd ungrzed) the second-growing seson fter fire nd ws greter thn the UNBURNED tretment. Over 9% of nnul for production ws comprised of ple lyssum, n introduced Old World weed. Herceous Productivity; Production vlues provided different perspective when evluting impcts of grzing fter fire ecuse residul mteril from previous yer s 12

19 UNBURNED BURN SUMMER 1 SUMMER 2 SPRING 1 SPRING 2 e d c c c l c ,, 2,,,,,,, Pre-urn Yer Figure 2. Herceous stnding crop (l c -1 ) for the vrious urn nd grzing tretments in Wyoming ig sgerush steppe, Vlues represent mens + one stndrd error. Different letters indicte significnt differences mong the tretments within yer. growth is removed prior to weighing (Fig. 4). In contrst to stnding crop results, differences mong the urn-grzed tretments nd the BURN tretment were less pprent for totl herceous nd perennil grss production in 25 nd 26. Neither summer grzing tretments differed from the BURN tretment for these response vriles. Production in the SPRING 1 nd SPRING 2 tretments ws less thn the BURN nd oth summer tretments ecuse of herge removl y livestock in 25. Despite iomss removl, herceous nd perennil grss production ws greter in SPRING 1 nd SPRING 2 tretments thn the UNBURNED tretment in 25. In 26, herceous nd perennil grss production did not differ mong the urn (grzed nd ungrzed) tretments. Herceous nd perennil grss production ws out two times greter in the BURN nd urned-grzed tretments thn the UNBURNED tretment in 26. Seed Production; Totl seed production ws greter in 25 thn 24 for ll tretments. Seed production ws greter in the BURN nd ll urn-grzed tretments thn the UNBURNED tretment in 25 (Fig. 5). Within the urn tretments grzing influenced totl seed production s well seed production of individul species. The BURN tretment hd greter totl seed production thn the SUMMER 1, SPRING 1, nd SPRING 2 tretments. 13

20 l c A. Perennil unchgrsses,,,, c, 15,,,, B. Snderg's 22 luegrss c,c,c 26 X Dt l c ,,,, l c -1 l c C. Perennil 26 Fors,,,, X Dt D. Annul 22 Fors UNBURNED BURN SUMMER 1 SUMMER 2 SPRING 1 SPRING 2 X Dt,,,, Pre-urn Yer,,,, Figure 3. Functionl group stnding crop vlues (l c -1 ) for the vrious urn nd grzing tretments in Wyoming ig sgerush steppe, 21-26; A) Perennil unch grsses; B) Snderg s luegrss; C) Perennil Fors; nd D) Annul fors. Vlues represent mens + one stndrd error. Different lower-cse letters indicte significnt differences mong the tretments within yer. 14

21 l c c c c A. Herceous 2 l c c c c B. Perennil Grss 2 l c C. Snderg's 26 luegrss 15 UNBURNED Yer BURN SUMMER 1 SUMMER 2 SPRING 1 1 SPRING Yer Figure 4. Production vlues (l c -1 ) for A) Herceous, B) Perennil unchgrsses, nd C) Snderg s luegrss for the vrious urn nd grzing tretments in Wyoming ig sgerush steppe, 25-26; Vlues represent mens + one stndrd error. Different lower-cse letters indicte significnt differences (p<.5) mong the tretments within yer. 15

22 8 A. Totl Seed Production e de 6 d d d l c -1 4 c 2 4 B. Blueunch whetgrss l c Yer c C. Idho fescue 24 c 25 l c l c D. Squirreltil l c E. Thurers needlegrss 24 UNBURNED c BURN 25 c c c SUMMER Yer 1 SUMMER 2 SPRING 1 SPRING 2 c Yer Figure 5. Seed production vlues (l c -1 ) for the vrious urn nd grzing tretments in Wyoming ig sgerush steppe, 25-26, Northern Gret sin Experimentl Rnge; A) Totl Perennil Bunchgrsses; B) Blueunch whetgrss; C) Idho fescue; D) Squirreltil; nd E) Thurer s needlegrss. 16

23 DISCUSSSION nd CONCLUSIONS The results from this study indicte tht moderte grzing following completion of the first growth cycle fter low severity fire does not limit herceous recovery in ig sgerush steppe. Tretment differences were considered minor when evluting community recovery fter fire. For most mesured vriles (re ground, litter cover, nd herceous cover, density, nd production) there were no differences mong grzed nd ungrzed urn tretments, prticulrly in the response yer of 26. The response of herceous vegettion fter fire, whether grzed or not, ws comprle to results from other post-fire work in the sgerush system. Herceous cover, stnding crop nd production in the BURN nd urn-grzed tretments equled or exceeded the UNBURNED tretment y the second or third yer fter fire. A fctor for the rpid nd progressive herceous response ws the low severity of the prescried fire. Fire cn negtively impct unchgrss species y killing individuls nd reducing plnt size especilly species with densely pcked culms such s Idho fescue nd Thurer s needlegrss. These were the most common perennil grss species on our study sites; however, neither species ws reduced in density, nd oth species demonstrted positive response y the second yer fter fire. Chetgrss nd other exotic species re mjor thret to mintining Wyoming ig sgerush communities. Our results demonstrted tht urning, with or without grzing, cn successfully stimulte herceous ntive species nd not result in n increse of chetgrss. There were likely two resons for the lck of chetgrss response; the pre-fire community ws lrgely composed of ntive perennils nd there ws limited mortlity of perennil grsses. High mortlity of perennils would like hve creted conditions tht would llow chetgrss to increse. The min exotic tht incresed nd comprised the ulk of for productivity nd composition fter fire ws ple lyssum. Informtion on the competitive ilities of lyssum is not ville, lthough it likely interferes with ntive nnul fors since root chrcteristics nd phenology pper to e similr. The presence of high densities of lyssum does not pper to ostruct the recovery of perennil grsses. Moss nd iologicl crust hd not recovered to pre-urn levels y the fourth yer fter fire. Recovery of mosses nd iologicl crusts fter fire vries depending on species nd plnt community composition ut recovery ppers to e lengthy process. In our study fire rther thn grzing ppers to hve hd the min impct on moss nd iotic crust. MANAGEMENT IMPLICATIONS The primry gols of post-fire ecosystem mngement re the recovery of ecologicl processes (hydrologic function, energy nd resource cpture), preferred plnt communities, wildlife hitt, nd economic use. In sgerush steppe plnt communities these gols re chieved y recovering the system to one comprised of perennil grsses, fors, nd shrus. This study demonstrted tht properly pplied livestock grzing fter one growth cycle following fire will not slow or reduce the recovery of herceous plnt communities in 17

24 Wyoming ig sgerush steppe. The study lso demonstrted tht grzing rest the first 2 yers fter fire to encourge herceous recovery my not e necessry in ll situtions. The results nd interprettions of this study must e considered under the conditions which it ws conducted. The trils were performed on single site; fire cused miniml mortlity to perennil unchgrsses; there ws lck of significnt weed presence; nd grzing protocols were strictly controlled. One or more of these elements will vry in other situtions nd generte host of different post-fire recovery scenrios. Study plots were smll nd we mnged to otin uniform grzing use. However, livestock tend not to grze uniformly in lrge pstures in the Gret Bsin, s distnce to wter nd topogrphy results in res of high, moderte, low, nd non-use. Grzing fter fire in lrger pstures nd for longer durtion would likely result in res of differentil use nd rtes of herceous recovery. The summer grzing tretments provided the most roust outcome regrding herceous recovery s our results were in greement with recent post-fire grzing nd defolition trils. Moderte grzing use fter perennil grss dormncy the first couple summers fter fire should not to reduce the recovery of post-fire herceous communities in sgerush steppe. This is the first such study of spring grzing in sgerush steppe fter fire nd trils only evluted defolition during vegettive nd erly oot stges of growth of the lrger perennil unchgrsses. As lluded to erlier, defolition of grsses in lter oot or flower stges might hve resulted in slower herceous recovery. At this point, grzing sgerush steppe in the spring the first two yers fter fire should e pplied cutiously. ACKNOWLEDGMENTS We would like to thnk numerous summer crew memers for ssistnce in the field nd lortory. Lori Ziegenhgen did much of the dt compiltion nd running the field crews in 23 nd 24. Mny thnks to Mtt Crlon, Lynn Crlon, nd Clre Poulsen for helping on the urn tem. REFERENCES BLM. 27. Emergency fire rehilittion hndook. United Sttes Bureu of Lnd Mngement, Wshington, DC. Bruce, L.B., B. Perrymn, K. Conley, nd K. McAdoo. 27. Cse Study: Grzing mngement on seeded nd unseeded post fire pulic rngelnds. The Professionl Animl Scientist 23: Bunting, S.C., R. Roerecht nd G.E. DeFosse Length nd timing of grzing on post urn productivity of two unchgrsses in n Idho experimentl rnge. Interntionl Journl of Wildlnd Fire 8:15-2. Jirik, S.J. nd S.C. Bunting Post-fire defolition response of Agropyron spictum nd Sitnion hystrix. Interntionl Journl of Wildlnd Fire 4:

25 Defolition Impcts on Aove nd Below-Ground Production in Riprin Sedge Community Chd S. Boyd nd Tony J. Svejcr SUMMARY In spite of the interest in grzing impcts on riprin systems, there is limited informtion on root response of riprin sedges to grzing. We evluted oth ove-ground nd elow-ground productivity in plots clipped in either June or July to 4-inch stule height. The study ws designed s rndomized lock with four replictions nd ws conducted during 24 nd 25. Root growth cores were used to hrvest nnul root growth, nd plots were clipped to estimte ove-ground end-of-seson stnding crop. Wter tles were higher in 25 for most of the growing seson. Clipping tretments reduced endof-seson ove-ground stnding crop, ut seson-long production (clipped mss + end-ofseson mss) ws less impcted y clipping tretment. Root mss ws only reduced y the July 25 clipping tretment, nd root length density ws not significntly impcted y ny tretment. In our study, root undnce ws very high nd resilient to clipping tretments. INTRODUCTION Previous reserch hs provided guidnce for ove-ground regrowth of riprin sedge communities following vrile timing nd intensity of defolition. This informtion serves s ckground mteril tht cn e used in developing mngement strtegies to meet endof-seson stule height ojectives nd provides guidnce for mximizing ove-ground production in grzed riprin systems. However, from functionl stndpoint, the importnce of elow-ground production in riprin communities is t lest equl to tht of ove-ground production. Roots re key to nutrient cquisition nd soil structure, nd in riprin systems function to hold nks in plce during high flow events. Bnk mintennce is prticulrly importnt ecuse nks help mintin chnnel structure nd the ssocited high wter tle necessry for riprin plnt species. At present there is only scnt informtion on the effects of defolition on elow-ground production in riprin sedge communities. The ojective of this study ws to determine the effects of clipping nd clipping dte on ove- nd elow-ground production in sedge-dominted riprin community. METHODS Dt were collected during the growing sesons of 24 nd 25. We used rndomized lock design with four sites (i.e. locks) djcent to Nicoll Creek, Hrney Co., Oregon. Sites were dominted y Nersk sedge nd were not grzed during the study. We used one clipping height (4-inches) nd two clipping dtes (June or July). Within site we locted eight, 4 x 2 inch plots. Adjcent plots were rndomly ssigned to experimentl (clipped) or control (unclipped) tretments. Experimentl plots were clipped in June or July. Six of the eight plots t one site nd four of the eight plots t nother site were grzed y cttle in erly August of 24 nd were omitted from nlyses for tht yer. We clipped ll plots to ground level in Octoer. All clipped vegettion ws oven-dried nd weighted. 19

26 Two 3-inch dimeter cores were excvted to 11.8 inches deep in ech plot nd filled with snd in the fll of 23 nd 24. Cores were hrvested in Septemer of 24 nd 25 y driving length of 2-inch chmfered PVC pipe into the center of the core. A shop-vc with n in-line collection reservoir ws then used to evcute the snd nd root mteril from the PVC pipe (Fig. 1). Hrvested roots nd soil were seprted in root wsher, scnned for root length density, oven dried, nd weighed. Wter tle elevtion ws mesured in PVC wells t i-weekly intervls from My through Septemer. Vlues were verged cross sites, within collection dte nd yer. Figure 1. Overview of root hrvest technique. Ingrowth cores (3 inch-dimeter) were excvted to 11.8 inch-depth in stremside-plots during the fll nd filled with snd. Cores were hrvested fter one yer using shop vcuum modified with PVC suction ttchment nd collection reservoir. RESULTS Groundwter ws t mximum depth in erly to mid August (pproximtely 3 to 4 inches elow the ground surfce, Fig. 2). Groundwter levels were within the rnge of tolernce for wet sedge communities (i.e., wter vilility ws not limiting fctor sedge growth). End-of-seson ove-ground stnding crop decresed with clipping (verge decline of 47% cross tretments) for ll time periods; prticulrly with July clipping (Fig. 3A). Seson-long production (clipped mss + end-of-seson stnding crop) ws less impcted y clipping nd decresed (verge decline of 15%) for clipped plots in July 24 nd June 25 (Fig. 3B). Timing of clipping hd no cler pttern of effect cross yers. Greter ove-ground production in 25 ws ssocited with incresed groundwter during the June-July period (Fig. 2). Root production nd root length density were not ffected y 2

27 Figure 2. Wter elevtion for plots used in sedge clipping study. Elevtions represent either the depth of stnding wter (positive vlues) or depth to ground wter (negtive vlues). Dt were verged over the 4 study sites, y dte nd within yer. clipping tretment with the exception of July, 25 when root production in July-clipped plots decresed y 34% compred to unclipped plots (Fig. 4). Decresed root production in 25 ws ssocited with incresed groundwter during the June-July period (Fig. 2). MANAGEMENT IMPLICATIONS An elevted wter tle ws ssocited with incresed ove-ground nd decresed elow-ground production. Clipping to 4 inches cn decrese end-of-seson ove-ground stnding crop; however, seson-long production is less impcted with no cler pttern of effect for timing of clipping. Root production ws not strongly impcted y clipping tretment nd ppers to e resilient to clipping. Our study confirmed tht root production in riprin sedge communities is very high compred to other ecosystems. Overll, our dt suggest tht elow-ground production would not e impired with moderte levels of herivory in June or July. REFERENCES Boyd, C.S. nd T.J. Svejcr. 24. Regrowth nd production of herceous riprin vegettion following defolition. Journl of Rnge Mngement 57: Clry, W.P. nd W.C. Leininger. 2. Stule height s tool for mngement of riprin res. Journl of Rnge Mngement 46:

28 Figure 3. Effects of clipping (4-inch stule height) nd timing of clipping on ove-ground production s mesured y end-of-seson stnding crop (A) nd seson-long production (B) for sedge-dominted riprin plots t Nicoll Creek, Hrney Co., Oregon. Differing letters within r pir indicte strong evidence of sttisticl difference. 22

29 Figure 4. Effects of clipping (4-inch stule height) nd timing of clipping on root production s mesured y weight (A) nd root-length density (B) for sedge-dominted riprin plots t Nicoll Creek, Hrney Co., Oregon. Differing letters within r pir indicte strong evidence of sttisticl difference. 23

30 Do Grzing Cttle Seek Nutritionlly Superior Portions of Pstures? Dve Gnskopp nd Dve Bohnert SUMMARY This study evluted the hypothesis tht grzing cttle will most often frequent nutritionlly superior portions of lrge pstures. Forge quntity/qulity chrcteristics were mpped mong three pstures nd cttle grzing ptterns susequently trcked with GPS collrs. Cttle preferred loctions with higher thn verge crude protein nd digestiility nd res with lower thn verge stnding crop nd neutrl detergent fier. These preferences likely explin dherence of cttle to historic grzing ptterns nd sesonl sptil moves of cttle in lrge pstures. Mngement prctices tht cn ffect desirle chnges in forge qulity, like mowing, urning, or prescried grzing, cn likely e used to ttrct stock to historiclly unused locles. INTRODUCTION On rngelnds, uneven or unmnged livestock distriution cn dversely ffect plnt community composition, riprin function, or displce wildlife. These issues hve historic precedents nd re still chllenge for those mnging rngelnds tody. A thorough understnding of fctors ffecting livestock distriution cn help lnd nd livestock mngers void or moderte deleterious effects. Optimum forging theory suggests nimls minimize energy expended nd mximize energy returns when grzing, ut forging decisions y lrge nimls t relevnt temporl nd sptil scles hve not een studied. The ojective of this reserch ws to test the hypothesis tht grzing cttle will seek nutritionlly superior portions of pstures. METHODS The reserch ws conducted in three 2+ cre pstures on the Northern Gret Bsin Experimentl Rnge 3 miles west of Burns, Oregon. Plnt communities include sprse western juniper overstory nd shru lyer dominted y Wyoming ig sgerush, mountin ig sgerush, or low sgerush. Prominent grsses include lueunch whetgrss, Idho fescue, or Snderg s luegrss depending on locle. Four hundred fifty three coordintes were estlished in n offset grid spnning the 3 pstures (Figure 1). With this rrngement, ech coordinte ws equidistnt (278 yds) from its six closest neighors. Coordintes were downloded to geogrphic positioning systems (GPS units), nd personnel dispersed to ech locle in mid June 24. At ech loction, frme ws dropped nd ll stnding grsses nd fors rooted therein were clipped to 1-inch stule. Susequent forge qulity ssys for ech smple included; crude protein (CP), neutrl detergent fier (NDF), nd digestiility s indexed y in situ dry mtter disppernce (ISDMD). Immeditely fter clipping, 15 cow/clf pirs were relesed to ech 24

31 Figure 1. Twenty foot contour lines nd positions of 453 forge smpling loctions used to ssess ptterns of forge quntity/qulity nd the distriution of grzing cttle on the Northern Gret Bsin Experimentl Rnge ner Burns, Oregon in June 24. of the three pstures. Four cows in ech group were equipped with GPS collrs to monitor their whereouts nd estlish their ctivities t 5-minute intervls (Fig. 2). Yield nd nutritionl dt were entered into GIS system nd mps rendered for ech of our forge quntity/qulity ttriutes. These depicted the distriution of forge chrcteristics cross the pstures. The loctions of grzing cttle were susequently overlid on these sme imges, nd the GIS system sked to furnish the forge quntity/qulity composition for the entire psture nd for ech loction used y cttle (Figure 3). 25

32 Figure 2. A glol positioning system (GPS) collr used to trck movements nd ctivities of cttle in study evluting ptterns of forge quntity/qulity nd the distriution of grzing cttle on the Northern Gret Bsin Experimentl Rnge ner Burns, Oregon in June 24. RESULTS AND DISCUSSION Over the 15-dy tril, grzing cttle ccessed only out 25% of their totl psture re (Fig. 4). Cttle preferred res with higher thn verge crude protein nd forge digestiility nd lower thn verge stnding crop nd neutrl detergent fier. The crude protein composition of the pstures nd the res frequented y cttle re depicted in Figure 4. Crude protein of forge cross the pstures verged out 8.8% nd 64% of grzing cttle oservtions occurred in res exceeding tht vlue. Our initil thoughts were tht cttle would seek out the solute highest qulity res in the pstures, ut tht did not occur. We speculte tht ecuse the highest crude protein res mke up less tht 5% of the lndscpe, it is not efficient for cttle to expend the energy needed to find those limited resources. With out 35% of the re in ech psture furnishing more thn dequte forge qulity, there ws gin little physiologic need to serch for exceptionl herge. Results for forge digestiility nlyses pinted out the sme picture s the crude protein dt. Cttle lso fvored portions of the psture supporting lower thn verge stnding crop (Fig. 5). Clssicl studies where forge qulity is constnt cross psture suggest cttle will seek res where their forge intke rte cn e mximized. Tht is typiclly mong res supporting the highest stnding crop. We found out 6% of our grzing cttle oservtions in res tht supported less thn verge stnding crop (318 ls cre -1 ). 26

33 Figure 3. A mp depicting the crude protein content of forge in Rnge 2 nd the loctions used y grzing cttle in study evluting forge qulity ptterns nd the distriution of cttle cross the lndscpe in June 24 on the Northern Gret Bsin Experimentl Rnge ner Burns, Oregon. Erlier studies t the experiment sttion hve shown tht cttle re very sensitive to nd intolernt of stnding ded strw intermingled with green herge. We speculte tht cttle were voiding our most productive sites ecuse they lso supported n undnce of wolfy forge. Consistent with our stnding crop findings, cttle lso fvored loctions supporting low neutrl detergent fier (dt not shown). High levels of fier in forges re ssocited with reduced digestiility nd intke y herivores, so we would expect cttle to void high fier sites. 27

34 CONCLUSIONS Consistent with optimum forging theory, grzing cttle most frequently used portions of pstures exhiiting higher thn verge crude protein nd forge digestiility nd lower thn verge stnding crop nd neutrl detergent fier. We speculte such preferences my explin the sesonl movements we see y cttle in lrge pstures s the growing nd grzing sesons dvnce. Fidelity to historic grzing ptterns, distriution shifts to recently urned locles, sesonl moves to riprin sites, nd lte-summer movements of cttle to sites supporting pltle shrus re likely ll responses to chnging lndscpe nutritionl dynmics. Mngement prctices tht lter the nutritionl chrcter of the lndscpe like prescried urns, fertiliztion, mowing, controlled grzing, or strtegic supplement plcement will likely e successful t ltering grzing distriution nd should e useful mngement tools for ttrcting cttle to historiclly unused locles. Figure 4. Percentges of the lndscpe nd grzing cttle oserved in 13 crude protein clsses smpled mong 3 pstures on the Northern Gret Bsin Experimentl Rnge in June 24 during study ssessing lndscpe nutritionl ptterns nd their effects on cttle distriution. A - eneth the X xis indictes clss ws voided y cttle. A implies clss ws used y cttle roughly in proportion to its presence on the lndscpe, nd + designtion suggests the clss ws preferred y cttle. Clsses with no symols were not included in nlyses, ecuse they were minor components of the lndscpe nd rrely visited. 28

35 Figure 5. Percentges of the lndscpe nd grzing cttle oserved in 13 stnding crop clsses smpled mong 3 pstures on the Northern Gret Bsin Experimentl Rnge in June 24 during study ssessing lndscpe nutritionl ptterns nd their effects on cttle distriution. A - eneth the X xis indictes clss ws voided y cttle. A implies clss ws used y cttle roughly in proportion to its presence on the lndscpe, nd + designtion suggests the clss ws preferred y cttle. Clsses with no symols were not included in nlyses, ecuse they were minor components of the lndscpe nd rrely visited. 29

36 Medushed Ecology nd Mngement 3

37 Medushed Estlishment nd Dispersl in Sgerush-Bunchgrss Communities Kirk W. Dvies SUMMARY Medushed is n invsive nnul grss tht reduces iodiversity nd production of rngelnds. To prevent medushed invsion lnd mngers need to know more out its invsion process. Specificlly, 1) the timing nd sptil extent of medushed seed dispersl nd 2) the estlishment rtes nd interctions with plnt communities eing invded. Medushed seeds dispersed etween July nd Octoer nd did not disperse more thn 6.6 feet from their source, without humn or niml trnsport, suggesting tht reltively nrrow continment rriers round medushed infesttions my e sufficient to significntly slow spred. The ility of medushed to estlish in plnt community ws negtively correlted to lrge perennil grss density. Thus, mintining lrge perennil grss is criticl to preventing medushed invsion nd incresing lrge perennil grss density should reduce the susceptiility of site to medushed invsion. INTRODUCTION Medushed is n exotic nnul grss invding rngelnds in the western United Sttes. Its rpid spred into previously uninfested res is serious mngement concern s medushed invsion hs reduced the grzing cpcity of rngelnds y s much s 9%. Medushed litter lso hs slow decomposition rte which llows it to uild up over time nd suppress ntive plnts. The uild up of medushed litter lso increses the mount nd continuity of fine fuel, thus incresing fire frequency to the detriment of ntive vegettion. The result is often loss of ntive species nd dense monocultures of medushed. To prevent medushed invsion lnd mngers need to know more out its invsion process. Specificlly, 1) the timing nd sptil extent of medushed seed dispersl nd 2) the estlishment rtes nd interctions with plnt communities eing invded. METHODS The study ws conducted in the northwest foothills of Steens Mountin in southestern Oregon. Medushed dispersl ws mesured using sticky seed trps nd medushed estlishment ws mesured t 12 sites. Vegettion cover nd density y species were mesured t the 12 sites to determine their impct on medushed estlishment. Wyoming ig sgerush is the dominnt shru nd lueunch whetgrss or squirreltil is the dominnt lrge perennil grss depending on site. 31

38 RESULTS Most medushed seeds (449 ± 9 seeds 11 ft -2 ) dispersed less thn 1.6 ft from the invsion front (Fig 1.). From 1.6 to 6.6 ft As distnces from the invsion front incresed medushed seed dispersl decresed: t 1.6 ft wy, 148 ± 42 seeds 11 ft -2 were collected, nd t 6.6. ft wy 11 ± 6.3 seeds 11 ft -2 were collected. No seeds were collected eyond 6.6 ft. Medushed seeds dispersed from the prent plnts from erly July (2.3 ±.6 seeds/trnsect) to the end of Octoer (2.3 ±.8 seeds/trnsect). More seeds were trpped in August thn the other months (2 ± 4.9 seeds/trnsect). Medushed density ws negtively correlted to lrge perennil grss density nd positively correlted to nnul grss density of the preexisting plnt communities (Fig. 2). These correltions explin 82% of the vrition in medushed density (R 2 =.82). Medushed density ws not correlted to density or cover of Snderg luegrss nd for functionl groups, or to re ground nd litter vlues. Medushed cover ws lso negtively correlted with lrge perennil grss density (R 2 =.44). 6 d 5 4 Seed density (#*11 ft -2 ) 3 2 c Distnce from medushed infestion (ft) Figure 1. Medushed seed density (men + S.E.) trpped t different distnces from the medushed invsion summed cross smpling dtes, Steens Mountin, Oregon. Different lower cse letters indicte differences mong distnces (P <.5). 32

39 Medushed Density (#*11 ft -2 ) TACA = (PG) +.3(AG) (9.) (1.4) (.1) R 2 =.82, P = Perennil Grss Density (#*11 ft -2 ) Annul Grss Density (#*11 ft -2 ) Figure 2. Sctter plot of medushed density cross lrge perennil grss nd nnul grss densities of the preexisting plnt community with regression lines, Steens Mountin Oregon. TACA8 = medushed, PG = lrge perennil grss, nd AG = nnul grss. MANAGEMENT IMPLICATIONS Livestock nd vehicle trffic should proly e removed from medushed infested sgerush-steppe rngelnds during the period when seeds re dispersed to reduce the spred of medushed. Site differences nd etween-yer vriility in precipittion cn e expected to influence medushed seed development nd dispersl. Thus, livestock nd vehicle exclusion from infesttions my vry from yer-to-yer nd site-to-site. The reltively long period of medushed seed dispersl from July to Octoer my e n dpttion to increse the likelihood of dhesion to nimls. Continment zones round infesttions cn proly e reltively nrrow; however, correctly identifying the edge of the infesttion is criticl. Mny medushed infesttions hve diffuse oundry tht requires creful scrutiny to identify. Systemtic serching for nd erdiction of new stellite popultions will still e necessry to successfully contin medushed infesttions. More reserch is needed to quntify the dispersl of medushed y vehicles nd nimls, especilly when soils re sticky due to moisture ccumultion. Lrge perennil grsses pper to e criticl component of sgerush rngelnds tht re resistnt to medushed invsion. Promoting nd mintining lrge perennil grss should e mngement priority on rngelnds susceptile to medushed invsion. Lrge perennil grss nd nnul grss density my e useful indictors of site susceptiility to medushed invsion. 33

40 REFERENCES Bovey, R.W., D. Le Tourneu, nd L.C. Erickson The chemicl composition of medushed nd downy rome. Weeds 9: Dhl, B.E., nd E.W. Tisdle Environmentl fctors relting to medushed distriution. Journl of Rnge Mngement 28: Dvies, K.W., nd R.L. Sheley. 27. A conceptul frmework for preventing the sptil dispersl of invsive plnts. Weed Science 55: George, M.R Ecology nd mngement of medushed. Dvis, CA: University of Cliforni Rnge Science Report 23:1-3. Hironk, M The reltive rte of root development of chetgrss nd medushed. Journl of Rnge Mngement 14: Monco, T.A., T.M. Osmond, nd S.A. Dewey. 25. Medushed control with fll- nd spring-pplied hericides in northern Uth foothills. Weed Technology 19: Torell, P.J., L.C. Erickson, nd R.H. Hs The medushed prolem in Idho. Weeds 9: Young, J.A Ecology nd mngement of medushed (Tenitherum cput-meduse ssp. sperum [SIMK.] Melderis). Gret Bsin Nturlist 52:

41 Medushed Outperforms Squirreltil Jne Mngold nd Kert Young SUMMARY Understnding the ecologicl processes fostering invsion nd dominnce y medushed is centrl to its mngement. The ojectives of this study were 1) to quntify nd compre interference etween medushed nd squirreltil under different concentrtions of soil nitrogen (N) nd phoshorus(p) nd 2) to compre growth rtes of medushed nd squirreltil. We grew medushed nd squirreltil in n ddition series in greenhouse nd pplied one of four nutrient tretments weekly: 1) low N- low phosphorus (P) (no N or P dded), 2) low N-high P, 3) high N-low P, nd 4) high N-high P. After 7 dys density nd iomss y species were smpled. We lso grew individul medushed nd squirreltil plnts in control soil conditions. Biomss, lef re, nd root length were determined for ech species t 14-dy intervls over 72 dys. Regression models for medushed nd squirreltil suggested N ppered to e plying much lrger role thn P in interference etween the species. The high N tretment did not increse medushed s interference ility reltive to squirreltil s we hd hypothesized. Medushed typiclly imposed two to seven time s stronger influence on interference reltionships thn squirreltil. Medushed ccumulted iomss, lef re, nd root length twice s fst s squirreltil. Results from our study suggest tht medushed seedlings will dominte over squirreltil seedlings. To restore squirreltil to medushed-infested rngelnd, medushed densities should e reduced with integrted weed mngement strtegies. On medushedfree rngelnd, prevention, erly detection, nd erdiction progrms re criticl. INTRODUCTION Medushed (Tenitherum cput-meduse (L.) Nevski) is nonindigenous, invsive winter-nnul grss tht thretens rngelnd systems in the intermountin West. Medushed is estimted to occupy 2 million h. in the Gret Bsin where it displces ntive vegettion nd forms exclusive stnds. It my disrupt nutrient, wter, nd fire cycles nd is lmost worthless forge for livestock. When present, medushed my reduce forge production up to 8%. Rngelnd dominted y medushed is often devoid of competitive desirle plnts. In such cses, introducing nd estlishing competitive plnts is essentil for successful mngement of infesttions nd the restortion of desirle plnt communities. Squirreltil (Elymus elymoides (Rfin.) Swezey) hs een identified s potentil species for restortion of medushed-infested rnge nd wild lnd nd hs een oserved to estlish in medushed stnds over time. An erly- to mid-serl ntive unchgrss common to western rngelnd, it germintes cross rnge of soil tempertures nd its cool seson root growth my help explin its ility to compete with nnul grsses. A vriety of other ttriutes my help squirreltil compete with medushed including self-pollintion, wide ecotypic vrition, nd efficient seed dispersl mechnisms. 35

42 We conducted n ddition series study tht evluted the effects of nitrogen (N) nd phosphorus (P) dditions on the interference etween medushed nd squirreltil. Another study compred growth rtes of the two species. The overll ojectives were 1) to quntify nd compre interference etween medushed nd squirreltil under different concentrtions of soil N nd P, nd 2) to compre growth rtes of medushed nd squirreltil under soil N nd P vililities found in field soil collected loclly. We hypothesized tht 1) N nd P dditions would increse medushed s interference ility reltive to the ntive grss in the interference study nd 2) medushed would disply higher growth rtes nd iomss ccumultion thn squirreltil. METHODS Two studies were simultneously conducted in greenhouse t the Estern Oregon Agriculturl Reserch Center in Burns, Oregon, from My to August, 25. Medushed seed ws collected loclly nd squirreltil seed ws purchsed from L nd H Seed in southestern Wshington. Polyvinyl chloride pipe ws used to construct growth tues.5 m deep for the interference study nd 1. m deep for the growth nlysis study. Soil tht hd supported squirreltil nd medushed ws collected from two sites ner John Dy, Oregon, nd sieved through to remove rocks nd lrge roots. Soil ws mixed with concrete-grde snd nd plced in the growth tues. Seeds of oth species were uniformly scttered cross the surfce of ech tue, depending on the experiment, nd covered with pproximtely 2 mm of field soil. Interference study Medushed nd squirreltil were plnted into the prepred growth tues in n ddition series design. Five seed density levels of medushed (, 1, 5, 25, 125 pure live seeds per pot) were fully mixed with the sme five density levels for squirreltil seed for totl of 25 density comintions. Ech grouping of the 25 density comintions received one of four nutrient tretments nd ws replicted three times in ech of two seprte trils. Ech tril lsted pproximtely 7 dys. Ech plnting mtrix received one of four nutrient tretments weekly: 1) low N low P (LN-LP) ws the control with no N or P dded to the pots; 2) low N high P (LN-HP) dded 25 ml of 6 µm P solution in the form of clcium phosphte; 3) high N low P tretment (HN-LP) dded 25 ml of n 8,4 µm N solution in the forms of clcium nitrte nd potssium nitrte; nd 4) high N high P tretment (HN-HP) dded 25 ml of n 8,4 µm N nd 6 µm P solution in the forms of clcium nitrte, potssium nitrte, nd potssium phosphte. Growth tues were misted twice dily s needed throughout the study to prevent wter stress. After 7 dys, density per growth tue of ech species ws counted nd oveground iomss clipped pproximtely 5 mm ove the soil surfce. Aoveground iomss ws dried for 72 hours t 5 C nd weighed. Dt were grouped y tretment for ech tril nd fit to multiple liner regression. The inverse of medushed nd squirreltil individul oveground iomss per plnt ws 36

43 predicted using medushed nd squirreltil finl densities per growth tue s independent vriles. Models were of the form: y m -1 = β m + β mm N m + β ms N s (medushed) y s -1 = β s + β ss N s + β sm N m (squirreltil) where y m nd y s represent the verge oveground iomss per plnt for medushed nd squirreltil, respectively. The regression coefficients β m nd β s represented the mximum oveground iomss for medushed nd squirreltil plnt grown in isoltion, respectively. A smller numer indictes greter iomss due to the inverse opertion. β mm nd β ss represent the effect of species density upon its own iomss (intrspecific interference) from the medushed nd squirreltil models, respectively. β ms nd β sm represent the effect of the neighoring species density on the men iomss of the response species (interspecific interference). N m nd N s represented the density per growth tue of medushed nd squirreltil, respectively. Slopes from the regression models for ech nutrient tretment were compred y clculting vrince rtios. The reltive interference ility for oth species under ech nutrient tretment ws clculted y dividing the intrspecific interference coefficient y the interspecific interference coefficient. Growth nlysis study In two seprte trils, five seeds of medushed or squirreltil were uniformly scttered cross the surfce of 4 (2 for ech species per tril) prepred growth tues nd covered with pproximtely 2 mm of field soil. The density of ech growth tue ws reduced to one vigorous seedling following estlishment. Growth tues were misted twice dily s needed throughout the study to prevent wter stress. Ech tril lsted pproximtely 7 dys. No nutrient tretments were pplied, so N nd P levels were equivlent to the LN-LP (control) tretment in the interference study. Every 14 dys, ove- nd elow-ground iomss of four rndomly selected squirreltil nd four rndomly selected medushed plnts were hrvested. Aove nd elow ground iomss ws seprted, lef re ws quntified, nd root length ws determined. Aove nd elow ground iomss ws dried nd weighed. Root:shoot rtio ws clculted from ovend elow-ground iomss mesurements. Dt were nturl log trnsformed nd fit to liner regression to estimte the instntneous growth rte sed on totl iomss, lef re, nd root length over the 7-dy period. Slopes were compred y clculting vrince rtios. Interference Study RESULTS AND DISCUSSION For oth Tril 1 nd Tril 2, ll models predicting medushed or squirreltil oveground iomss were significnt (P<.1). Regression model coefficients for oth species generlly differed etween the high nd low N tretments, ut not etween the high 37

44 nd low P tretments (Tles 1 nd 2). Nitrogen ppered to e plying much lrger role thn P in interference etween medushed nd squirreltil. The invsive grss medushed outperformed the ntive grss squirreltil in ll spects of interference. High nutrient vilility did not increse medushed s interference ility reltive to squirreltil s hypothesized. In the low N tretments for Tril 1, the predicted mximum oveground iomss for n isolted medushed plnt (β m ) ws out.3 g (1/3.16 for low P nd 1/3.47 for high P), while the high N tretments resulted in nonsignificnt regression coefficient for predicted oveground iomss. Squirreltil predicted mximum oveground iomss for n isolted individul (β s ) rnged from out.7 g (1/15.2) to.15 g (1/6.71 nd 1/6.81) in the low N tretments cross trils. A nonsignificnt regression coefficient suggested the mximum iomss of n individul would e very lrge ecuse of the reciprocl opertion (i.e., 1/ ). In ll cses, the predicted mximum oveground iomss for medushed plnt ws greter thn tht of squirreltil plnt. In the medushed models intrspecific interference ws more intense thn interspecific interference, while in the squirreltil models interspecific interference ws more intense thn intrspecific interference. Intrspecific interference coefficients for medushed (β mm ) decresed from pproximtely.35 with low N tretments to.1 with high N tretments in Tril 1 nd.3 to.11 in Tril 2 (Tle 1). In the low N tretments in Tril 1, the interspecific interference coefficient (β ms ) ws not significnt, suggesting squirreltil density Tle 1. Tril 1 nd Tril 2 multiple liner regression models with medushed nd squirreltil growth tue density predicting the inverse of individul medushed iomss (g plnt -1 ). Tretment β m β mm β ms β mm / β ms r 2 Tril 1 lonlop 3.16 (1.25).34 (.2).6 (NS) 3.4 x 1 3 ().86 hinlop.33 (NS).11 (.).4 (.1) 2.57 ().96 lonhip 3.47 (1.52).37 (.2).4 (NS) 3.7 x 1 3 ().83 hinhip.16 (NS).11 (.).6 (.1) 1.92 ().97 Tril 2 lonlop 1.39 (NS).29 (.1).6 (.2) 4.74 ().92 hinlop -.3 (NS).11 (.).4 (.) 2.87 ().98 lonhip 1.3 (NS).31 (.1).4 (.2) 7.5 ().89 hinhip.3 (NS).11 (.).4 (.) 2.98 ().96 β m =inverse men iomss of n individul medushed plnt grown in isoltion, β mm =effect of medushed density on medushed iomss per plnt, β ms =effect of squirreltil density on medushed iomss per plnt. β mm / β ms =reltive interference rtio of the two species, nd r 2 =coefficient of determintion. Numers in prentheses re stndrd errors for coefficients significntly different from zero (P=.5). NS=not significnt. Slopes of models with different letters in prentheses in the reltive interference rtio column re sttisticlly different from one nother. 38

45 hd no effect on medushed iomss. Interspecific interference incresed to out.5 in the high N tretments in Tril 1 nd in ll tretments during Tril 2. Squirreltil intrspecific interference coefficients (β ss ) decresed from low N tretments to high N tretments with vlues rnging from.41 to.1, respectively (Tle 2). Interspecific interference coefficients (β sm ) rnged from.4 to.76 nd were generlly higher in high N tretments. All of the reltive interference rtios (β mm /β ms ) for medushed were greter thn one, especilly in the high N tretments, while the opposite ws true for squirreltil (β ss/ β sm < 1) (Tles 1 nd 2). This suggests medushed ws imposing more interference on oth its own iomss nd on squirreltil iomss thn ws squirreltil on medushed iomss or its own iomss. The effect of medushed density on medushed iomss ws generlly out 2 to 7 times greter thn the effect of squirreltil density on medushed iomss. The effect of squirreltil density on its own iomss ws generlly out 25-8% of the effect of medushed density on squirreltil iomss. Tle 2. Tril 1 nd Tril 2 multiple liner regression models with medushed nd squirreltil growth tue density predicting the inverse of individul squirreltil iomss (g plnt -1 ). Tretment β s β ss β sm β ss / β sm r 2 Tril 1 lonlop 15.2 (5.3).41 (.13).52 (.1).8 ().43 hinlop 1.89 (NS).12 (.4).43 (.3).26 ().82 lonhip (NS).42 (.2).76 (.14).55 ().44 hinhip 3.61 (NS).1 (NS).4 (.5) 2.5 x 1-4 ().62 Tril 2 lonlop 6.71 (2.86).33 (.5).44 (.4).75 ().73 hinlop 3.62 (NS).12 (.4).26 (.3).45 ().6 lonhip 6.81 (2.68).31 (.5).58 (.4).54 ().83 hinhip.92 (NS).18 (.3).24 (.2).73 ().74 β s =inverse men iomss of n individul squirreltil plnt grown in isoltion, β ss =effect of squirreltil density on squirreltil iomss per plnt, β sm =effect of medushed density on squirreltil iomss per plnt. β ss / β sm =reltive interference rtio of the two species nd r 2 =coefficient of determintion. Numers in prentheses re stndrd errors for coefficients significntly different from zero (P=.5). NS=not significnt. Slopes of models with different letters in prentheses in the reltive interference rtio column re sttisticlly different from one nother. 39

46 Growth Anlysis Study Dt collected from ech tril were nlyzed seprtely ecuse iomss ccumultion ws greter in Tril 2. Only results from Tril 2 re presented grphiclly (Fig. 1), ut results were similr cross trils. Consistent with our second hypothesis, we found tht medushed grew igger nd fster thn squirreltil. Invsive nd/or nnul species commonly disply high growth rtes nd lrge iomss ccumultion. Medushed growth rte ws higher thn squirreltil s in oth trils. Medushed totl iomss incresed y.11 g/dy while squirreltil totl iomss incresed y.5 g/dy during Tril 2 (Fig. 1). During Tril 1 medushed totl iomss incresed y.5 g/dy compred to.2 g/dy increse for squirreltil. A high growth rte is one mechnism tht my e criticl to medushed s success. A species with higher growth rte my dominte ecuse it cn estlish fster, increse in size more quickly, nd gin more ccess to resources thn slower growing species. Medushed generlly ccumulted lef re nd root length t fster rte thn squirreltil in oth trils. Medushed lef re incresed y out 4.5 cm 2 /dy nd 13.3 cm 2 /dy in Tril 1 nd Tril 2, respectively (Figure 1); squirreltil lef re incresed y out 4.9 nd 2.3 cm 2 /dy for Tril 1 nd Tril 2, respectively (Figure 1). Root length ccumultion showed similr trends with medushed root length incresing out 2.5 (Tril 1) to 4 (Tril 2) times fster thn squirreltil root length (Figure 1c). However, squirreltil root:shoot rtios sed on iomss were pproximtely 1.5 times greter thn medushed root:shoot rtios in Tril 2 t 3, 44, nd 58 dys post plnting. The growth nlysis study supported results of the interference study nd offers importnt insight into why medushed ppered to impose more interference thn squirreltil. When resources such s N re plentiful, the species tht is most cple of growing rpidly nd exploiting ville resources, in this cse medushed, will enefit the most. Medushed my e outperforming squirreltil vi resource (i.e. N) preemption ecuse 1) medushed displyed fster growth rtes nd greter increses in lef re nd root length thn squirreltil nd 2) medushed individul plnt weight (i.e. totl iomss) ws lwys greter thn tht of squirreltil. Furthermore, the influence of medushed on its own iomss ws more intense thn the influence of squirreltil on medushed s iomss, nd this intensity ws lessened when N ws incresed. Squirreltil hs een oserved to estlish in medushed stnds over time, which is contrdictory to wht our results might predict. One reson for this discrepncy my e ecuse squirreltil is highly ecotypic. Ecotypic vrition my provide genotypes tht resist medushed invsion more so thn others. Yet nother reson my e ecuse our study quntified seedling-seedling interference insted of mture squirreltil-medushed seedling interference. The perennil nture of squirreltil nd its tendency to hve higher root to shoot rtios, s indicted in the growth nlysis, my confer some dvntges over time tht we were not le to distinguish in this study. 4

47 3 2 squirreltil medushed clculted vrince rtio = 1.9 Nturl log totl iomss (g) y =.19x R 2 =.94 y =.94x R 2 = dys post plnting 8 7 squirreltil medushed clculted vrince rtio = 14.6 Nturl log lef re (cm 2 ) y =.96x +.17 R 2 =.92 y =.77x +.25 R 2 = dys post plnting squireltil medushed clculted vrince rtio = 23.5 Nturl log root length (cm) y =.11x R 2 =.95 y =.73x R 2 = dys post plnting Figure 1. Growth rte (), lef re increse (), nd root length increse (c) of isolted individuls of squirreltil nd medushed for Tril 2. Dt were linerized y tking the nturl log of mesured totl iomss, lef re, nd root lengths to llow comprison of slopes. Criticl vlue of vrince rtio used to compre slopes (α =.5) = 6.3. Clculted vrince rtio > criticl vlue suggests slopes re different. 41

48 IMPLICATIONS The results from our study suggest tht squirreltil is not likely to effectively compete with medushed in the seedling stge. Therefore, in order to restore squirreltil to rngelnd dominted y medushed, densities of medushed seed in the seed nk should e reduced y crefully timing vrious integrted weed mngement strtegies like urning, hericide use, nd grzing. Seeding squirreltil t high rtes my lso improve estlishment success. Once estlished, squirreltil my e le to mintin itself through perennil resource lloction ptterns, ut would not likely erdicte medushed. We suspect tht revegettion of medushed infested rngelnd will require lrge quntities of resources nd time. Aggressive nd comprehensive prevention progrms tht include erly detection nd erdiction re criticl for conserving rngelnd tht is currently reltively medushed-free This pper is n ridged version of Young, K. nd J. Mngold. 28. Medushed (Tenitherum cput-meduse) outperforms squirreltil (Elymus elymoides) through interference nd growth rte. Invsive Plnt Science nd Mngement 1: REFERENCES Hrdegree, S.P., T. A. Jones, nd S. S. Vn Vctor. 22. Vriility in therml response of primed nd non-primed seeds of squirreltil [Elymus elymoides (Rf.) Swezey nd Elymus multisetus (J. G. Smith) M. E. Jones]. Annls of Botny 89: Hironk, M The reltive rte of root development of chetgrss nd medushed. Journl of Rnge Mngement 14: Hironk, M. nd B.W. Sindelr Reproductive success of squirreltil in medushed infested rnges. Journl of Rnge Mngement 26: Jones, T.A Viewpoint: the present sttus nd future prospects of squirreltil reserch. Journl of Rnge Mngement 51: Jones, T.A., D.C. Nielson, J. T. Arrendondo, nd M. G. Redinugh. 23. Chrcteriztion of diversity mong 3 squirreltil tx. Journl of Rnge Mngement 56: Miller, H.C., D. Clusnitzer, nd M. M. Bormn Medushed. Pges in R. L. Sheley nd J. K. Petroff, eds. Biology nd mngement of noxious rngelnd weeds. Corvllis, OR: Oregon Stte University Press. Young, J. A Ecology nd mngement of medushed (Tenitherum cput-meduse ssp. Asperum [Simk.] Melderis). Gret Bsin Nturlist 52:

49 Effects of Imzpic on Trget nd Nontrget Vegettion During Revegettion Roger L. Sheley, Michel F. Crpinelli, Kimerly J. Reever Morghn, And Edwrd A. Vsquez SUMMARY Medushed is n introduced, winter-nnul grss covering millions of cres of western rngelnds. It forms lrge monocultures nd hs dense thtch cover tht resists the estlishment of desirle vegettion. Prescried fire cn remove medushed litter nd improve plnt estlishment. Medushed control is fundmentl to estlishing desirle vegettion tht will, in turn, resist future invsion. Imzpic is n effective hericide for control of medushed, ut more informtion is needed on its effects on desirle vegettion. Therefore, existing medushed infesttions were urned t two different sites in June 23 to test how Imzpic ppliction rte nd timing ffected medushed, desirle seeded plnt species, nd other nontrget vegettion on urned nd unurned rngelnd in southestern Oregon. Following the urn, imzpic ws pplied t seven incresingly concentrted rtes etween July nd Octoer of 23 in rndomized strip-plot design field experiment. In Novemer 23, seven different desirle plnt species were drill-seeded seprtely cross the imzpic res. Dt on cover nd density of medushed nd seeded plnt species were collected in 24 nd 25. Cover dt of nontrget vegettion were collected in the summer of 25. Medushed cover ws the highest in control plots tht did not receive imzpic nd lowest in plots tht received the highest hericide rtes. Seeded plnt species estlished in the study plots, ut their response to hericide rte showed few consistent ptterns. For exmple, some of the seeded plnt species showed little response to hericide, wheres others ppered to estlish est t different hericides rtes, depending on site nd whether the plots were urned or unurned. Site nd urn tretment lso ffected how imzpic rte or ppliction month influenced cover of perennil or nnul grsses or fors. INTRODUCTION AND OBJECTIVES Medushed is currently one of the gretest threts to plnt communities in the Gret Bsin. Medushed is cple of forming monoculture stnds tht urn redily nd resist reestlishment of ntive vegettion. Medushed is lso lrgely unpltle y livestock; thus, invsion results in economic losses to rurl communities, nd it is reported tht medushed-dominted rnges hve suffered 4 to 7% reduction in grzing cpcity. This ggressive, invsive, winter-nnul grss ntive to Eursi grows in vriety of environments ut is restricted to regions with 1 to 4 inches nnul precipittion with hot dry summers nd cool wet winters. Medushed commonly occupies cly soils tht mintin soil moisture lte into the growing seson, in rid environments, nd in well-developed lom soils where soil moisture is sufficient for the plnt to mture. Some success in controlling medushed popultions hs een chieved y hericide use; however there hs een very little pulished reserch on the effectiveness of imzpic t 43

50 controlling medushed. Previous reserch suggests tht one chllenge of mnging medushed with plntings of competitive species is to find rte of imzpic tht will offer control of medushed without dmging non-trget vegettion. More reserch is needed to understnd how medushed will respond to different rtes of imzpic nd different hericide ppliction timings nd whether those ptterns re the sme in urned nd unurned fields. An integrtive mngement strtegy tht comines hericides, fire, nd reseeding of competitive plnt species cn crete diverse plnt community tht will resist future invsions. Perennil grss plntings my provide plnt community etter le to resist further invsion of nnul weeds such s medushed, ut these plntings my fil if competition from nnul invders is not controlled. The purpose of this study ws to evlute the effects of imzpic rte nd timing of ppliction on vrious grss species nd fors in urned nd non-urned pstures. METHODS The study ws conducted t two sites in estern Oregon from 23 to 25. The first site, Mullin Rnch is locted ner John Dy, Oregon (Grnt County, lt 44 26' 5.5" N, long ' 18.29" W). The second site, Lm Rnch, is locted ner Drewsey, Oregon (Grnt County, lt 43 26' 54.98" N, long ' 43.94" W). At ech site, 5-cre portion of n existing medushed infesttion ws urned in June 23. Another 5-cre portion ws left s n unurned control. On oth the urned nd unurned res t ech site, imzpic ws pplied t one of four times nd one of seven (, 1., 1.5, 2., 2.5, nd 3. ounces per cre) hericide ppliction rtes. The timing of hericide ppliction ws lte-july, lte-august, lte-septemer, nd lte-octoer 23, nd ech ppliction month ws replicted seven times. In Novemer 23, monocultures of seven plnt species commonly used in revegettion were drill-seeded perpendiculrly cross the imzpic treted res, resulting in three replictions of the seeding tretment. These were: (1) thickspike whetgrss (ELLA), (2) Sierin whetgrss (AGFR), (2) lueunch whetgrss (PSSP), (3) squirreltil (ELEL), (4) Snderg luegrss (POSE), (5) winterft (KRLA), (6) forge kochi (KOPR), nd (7) control, unseeded. One row in ech of the three replictions ws left unseeded s control. Medushed Cover RESULTS Medushed cover tended to e highest in the plots tht received no imzpic nd lowest in plots tht received the three highest ppliction rtes. Medushed cover lso tended to e higher in the unurned plots (Figs. 1 nd 2). However, lthough imzpic reduced medushed cover in oth yers, even the highest concentrtions of imzpic did not reduce medushed cover to zero. Appliction timing hd smll effect on hericide effectiveness; July pplictions were slightly less effective thn pplictions in the other 3 months. Men medushed cover ws lower in urned plots thn in unurned plots, nd tht difference in cover ws especilly noticele in plots tht received no imzpic or low imzpic concentrtions (Figs. 1 nd 2). 44

51 24 Burned Plots 24 Unurned Plots Medushed Cover (%) A July August Septemer Octoer Medushed Cover (%) B July August Septemer Octoer Rte (ounces i/cre) Rte (ounces i/cre) 25 Burned Plots 25 Unurned Plots Medushed Cover (%) C July August Septemer Octoer Medushed Cover (%) D July August Septemer Octoer Rte (ounces i/cre) Rte (ounces i/cre) Figure 1. Lm Rnch (Drewsey, OR) medushed cover in response to hericide rte nd ppliction month. Vlues re mens ± SE. (A) 24 urned plots, (B) 24 unurned plots, (C) 25 urned plots, nd (D) 25 unurned plots. Seeded Plnt Species Cover nd Density Cover y seeded species ws low throughout this study; the verge cover ws elow 3% t Lm Rnch nd under 9% t Mullin Rnch. However, the seeded species were estlished t these two sites. Perennil grss cover did not show cler pttern with regrd to hericide rte or hericide ppliction month. The cover of nnul grsses other thn medushed tended to e higher t the lower imzpic ppliction rtes, especilly in the first yer of the study. In ddition, no consistent pttern of response y perennil fors to imzpic ppliction rte ws seen, with the exception of few unurned plots tht showed higher coverge y perennil fors t higher rtes. The reltionship etween nnul for cover nd hericide rte vried gretly etween yers nd showed few consistent ptterns. In some of the plots, the reltionship of nnul for cover to imzpic rte switched etween yers; in the first yer of the study, nnul for cover ws lowest in the plots tht received the highest rtes of imzpic, ut y the second yer of the study, nnul for cover ws lowest in plots tht received the lowest rte of imzpic. 45

52 The ptterns seen for seeded species density t Lm Rnch in 25 were similr to those seen for seeded species cover, nd few ptterns etween density nd hericide rte were visile. As seen for Lm Rnch, the results for seeded species density t Mullin Rnch in 25 were similr to those for seeded species cover, with no cler pttern etween hericide rte nd density. However, differences etween the urned nd unurned plots were quite pronounced. The highest density ws seen for Sierin whetgrss, followed y squirreltil, in the urned plots, wheres in the unurned plots, the highest density ws seen for Snderg luegrss. Seeded perennil grsses pper to hve estlished more successfully thn seeded fors during this study (dt not shown). There ws lrge difference in for estlishment etween sites nd response to urning, with winterft only estlishing in the unurned plots t Lm Rnch nd not t ll t Mullin Rnch. Estlishment of ll five perennil grss species ws higher thn for estlishment, nd some, such s Sierin whetgrss nd squirreltil, did well on mny plots. 24 Burned Plots 24 Unurned Plots Medushed Cover (%) A July August Septemer Octoer Medushed Cover (%) B July August Septemer Octoer Rte (ounces i/cre) Rte (ounces i/cre) 25 Burned Plots 25 Unurned Plots Medushed Cover (%) C July August Septemer Octoer Medushed Cover (%) D July August Septemer Octoer Rte (ounces i/cre) Rte (ounces i/cre) Figure 2. Mullin Rnch (John Dy, OR) medushed cover in response to hericide rte nd ppliction month. Vlues re mens ± SE. (A) 24 urned plots, (B) 24 unurned plots, (C) 25 urned plots, nd (D) 25 unurned plots. 46

53 MANAGEMENT IMPLICATIONS Imzpic ppliction offers effective control of medushed efore seeding with desirle species, nd tht control is more effective in plots tht hve een urned to remove medushed thtch. The results from this study suggest tht imzpic lone cn control medushed in the initil yer; however, in susequent yers, medushed is likely to reinfest the re. Other hericides cn lso e used to control medushed, such s glyphoste, trzine, romcil, siduron with piclorm, nd dlpon. Creful selection nd ppliction of these hericides cn llow control of medushed with miniml dmge to desired species. Using n integrted mngement strtegy tht uses prescried urns in conjunction with imzpic cn potentilly result in etter control t lower hericide concentrtions, lthough tht control my e of short durtion. The erliest ppliction of imzpic in July ppers to e less effective thn lter ppliction. Fors my e more difficult to estlish during medushed control nd revegettion. Imzpic ppers to control nnul grsses other thn medushed during the first yer fter ppliction, lthough tht control my only e of short durtion s those grsses cn sprout redily from seed the yer fter mngement. Furthermore, our study found few consistent ptterns relting the rte of imzpic to the cover of nnul or perennil fors. REFERENCES George, M. R Ecology nd mngement of Medushed. Dvis, CA: University of Cliforni. Rnge Science Report 32, 1-3. Monco, T. A., T. M. Osmond, nd S. A. Dewey. 25. Medushed control with fll- nd spring-pplied hericides on Northern Uth foothills. Weed Technology 19: Young, J. A., R. A. Evns, nd J. Roison Influence of repeted nnul urning on medushed community. Journl of Rnge Mngement 25:

54 Crested Whetgrss Defolition Intensity nd Seson of Use on Medushed Invsion Roger L. Sheley, Brett S. Binghm, Tony J. Svejcr, nd Edwrd A. Vsquez SUMMARY The ojective of this study ws to determine the effects of crested whetgrss defolition intensity nd timing on medushed density nd iomss. Eighteen tretments (six defolition levels, three sesons of defolition) were pplied to 21.5-ft 2 plots on two sites with vrying cly content. Plnts were clipped in 24 nd 25. Crested whetgrss ws hnd clipped to defolition levels of %, 2%, 4%, 6%, 8%, nd 1% in the spring, summer, nd fll. Density of crested whetgrss nd medushed ws smpled in June 25 nd 26, ut their iomss ws hrvested only in 26. Over the two sesons, site hd much more of n impct on medushed invsion thn either defolition intensity or timing of defolition. The results support previous suggestions tht clyey soils fvor medushed nd tht perennil grsses with high iomss cn resist this invsive species. On the clyey site where medushed did persist, fll defolition of crested whetgrss reduced the density of this invsive species y 5% or more compred to spring defolition. Given the developmentl pttern of medushed, the gol of ny mngement progrm should e to mximize resource use y the desirle plnt species from April to lte July. INTRODUCTION AND OBJECTIVES Throughout the Gret Bsin nd the surrounding ecosystems, mjor fctor ffecting rngelnd resources, fires, nd wtershed functioning is invsion y the winter nnul grss, medushed. This nnul grss hs invded millions of cres throughout the western United Sttes, nd continues to spred t rpid rte. Within the sgerush steppe, medushed ggressively displces perennil grsses y preempting soil resources, nd frequent fires destroy the shru portion of the plnt community. Medushed-dominted sites hve 5 to 8 percent less grzing cpcity thn the originl ntive plnt community. Most ecologists elieve tht medushed reduces plnt nd niml diversity nd richness, reduces suitle hitt for wildlife, ccelertes erosion, nd lters nutrient cycles, hydrologic cycles, nd energy flow. Mngers elieve this invsive plnt species is ecoming incresingly common on cly lom nd lom soils. However, it might e more competitive nd persistent on cly soils even though it hs the cpcity to encroch in ntive shru-steppe plnt communities on lom soils. It invdes distured res, nd in the sence of competition, medushed demonstrtes geometric popultion growth. Timing, intensity, nd frequency of defolition ffect the competitive interctions etween invsive species nd perennil grsses, nd thus influence the ility of perennil grss to withstnd invsive plnt species invsion. An pproprite comintion of timing, 48

55 intensity, nd frequency of grzing should llow desired species to remin competitive with invsive species. However, little is known out the effects of defolition on medushed estlishment in stnds of perennil grsses. The ojective of this study ws to determine the effects of crested whetgrss defolition intensity nd timing on medushed density nd iomss. METHODS This study ws conducted from 24 to 26 on two sites. Both sites were within the Wyoming ig sge/lueunch whetgrss community types of estern Oregon. Site one ws locted ner Ventor, Oregon ner the Colemn Creek Rnch (lt 43 33' " N, long ' 42.73" W), nd site two ws locted ner the south end of Wrm Springs Reservoir (lt 43 26' " N, long ' 48.53" W) ner Riverside, Oregon. This site, especilly with cly soils, is susceptile to invsion y medushed. Eighteen tretments (six defolition levels, three sesons of defolition) were pplied to 21.5-ft 2 plots. Plnts were clipped in 24 nd 25. Crested whetgrss ws hnd clipped y weight to defolition levels of %, 2%, 4%, 6%, 8%, nd 1% in the spring, summer, nd fll. Density ws smpled in 25 nd 26 nd on 23 June 26, the oveground iomss of crested whetgrss nd medushed ws hrvested, dried nd weighed. RESULTS Biomss Removed In 24, the mount of iomss removed ws similr t oth sites during ech seson of defolition (Fig. 1). Except for the summer of 24 t Colemn Creek, the clipping tretment resulted in continuous increse in iomss removed, ut the mount of iomss removed did not lwys significntly differ from the djcent defolition level. In the summer t Colemn Creek, defolition levels trgeted to receive 6%, 8%, nd 1% crested whetgrss removl received the sme clipping intensity. In 25, cross defolition tretments, Colemn Creek yielded less crested whetgrss iomss when clipped in the spring or fll thn in 24. At Wrm Springs, crested whetgrss removed ws higher in 25 thn in 24 cross ll defolition intensities. However, the mount of iomss removed in the spring of 24 ws the sme s tht removed in the spring of 25 t Wrm Springs. Crested Whetgrss nd Medushed, 25 In 25, the only fctor tht ffected crested whetgrss or medushed density ws site. At Colemn Creek, crested whetgrss produced 129 tillers per 1.8 ft 2, wheres it produced 228 tillers per 1.8 ft 2 t Wrm Springs when verged cross ll tretments tht yer. Medushed produced 125 plnts per 1.8 ft 2 t Colemn Creek nd only 2 plnts per 1.8 ft 2 t Wrm Springs in

56 Crested whetgrss removl (ounces/1.8 ft 2 ) % 4% 6% 8% 1% Colemn Creek 24 Spring Summer Fll Crested whetgrss removl (ounces/1.8 ft 2 ) % 4% 6% 8% 1% Colemn Creek 25 Spring Summer Fll Crested whetgrss removl (ounces/1.8 ft 2 ) % 4% 6% 8% 1% W rm Springs 24 Spring Summer Fll Crested whetgrss removl (ounces/1.8 ft 2 ) % 4% 6% 8% 1% W rm Springs 25 Spring Summer Fll Figure 1. Biomss of crested whetgrss removed from plots t Colemn Creek nd Wrm Spring in 24 nd 25. Error rs ± 1 SE. Crested Whetgrss nd Medushed, 26 Crested whetgrss density nd iomss depended on site in 26. This grss produced 122 tillers per 1.8 ft 2 t Colemn Creek nd 366 tillers per 1.8 ft 2 t Wrm Springs when verged cross ll tretments. Crested whetgrss iomss followed similr pttern tht yer. It produced.82 oz. per 1.8 ft 2 t Colemn Creek nd only.15 oz. per 1.8 ft 2 t Wrm Springs when verged cross ll tretments. Medushed density nd iomss depended on site nd intercted with seson of defolition, ut not defolition intensity in 26. At Colemn Creek, defoliting crested whetgrss in either the spring or summer yielded out twice the numer of medushed plnts thn defoliting the unchgrss in the fll (Fig. 2). By 26, there were no detectle medushed plnts t Wrm Springs. Clipping crested whetgrss in the summer yielded the higher medushed iomss t Colemn Creek, which ws out.2 oz. per 1.8 ft 2 (Fig. 3). Spring crested whetgrss defolition reduced the medushed yield to out.2 oz. per 1.8 ft 2, wheres defolition in the fll produced out out.1 oz. per 1.8 ft 2 of this invsive plnt species. Becuse there were no medushed plnts t Wrm Springs, there ws no iomss of this invsive species in 26. 5

57 Figure 2. Effect of seson of defolition on medushed density in 26. Error rs represent ± 1 SE. MANAGEMENT IMPLICATIONS Our study supports the conclusion tht on clyey loms nd lomy soils, estlished crested whetgrss is proly cple of resisting invsion y medushed if the plnts re mnged to llow them to fully regin their iomss production from one grzing seson to the next. We elieve tht the response of crested whetgrss to defolition, nd potentilly grzing, nd corresponding invsion of medushed follows ell-shped curve on these soil textures. Hevy repeted defolition in the spring prevents crested whetgrss from fully recovering its iomss production y the following grzing event nd llows invsion. On the other end of the curve, no defolition llows crested whetgrss to ecome old nd decdent, nd in turn, impedes its ility to rpidly grow nd develop competitive root system in the spring. Our study shows tht periodic defolition of crested whetgrss is required to mintin enough young, vigorous growth to successfully outcompete medushed. At one site, defoliting crested whetgrss in the summer or fll stimulted enough ggressive growth to completely remove ll medushed tht hd estlished in the prior yer. Without other mjor disturnces, moderte to hevy grzing intensity pplied to crested whetgrss while lternting the seson of use should prevent invsion of medushed on cly lom soils. 51

58 .35 Medushed (ounces/1.8 ft 2 ) c d Colemn creek Wrm springs Figure 3. Effect of seson of defolition on medushed iomss in 26. Error rs represent ± 1 SE. REFERENCES Briske, D. D. nd J. H. Richrds Plnt responses to defolition: physiologicl, morphologicl nd demogrphic evlution. In: D. J. Bedunh nd R. E. Soseee [EDS]. Wildlnd plnts: physiologicl ecology nd developmentl morphology. Denver, CO, USA: Society of Rnge Mngement. P Cook, C. W., L. A. Stodrt, nd F. E. Kinsinger Reponses of crested whetgrss to vrious clipping tretments. Ecologicl Monogrphs 28: Jcos, J. S. nd R. L. Sheley Grss defolition intensity, frequency, nd seson effects on spotted knpweed invsion. Journl of Rnge Mngement 52:

59 Western Juniper Ecology nd Mngement 53

60 A History of Woodlnd Dynmics in the Owyhee s: Encrochment, Stnd Closure, Understory Dynmics, nd Tree Biomss Rick Miller, Jime Rtchford, nd Dustin Johnson INTRODUCTION Piñon nd juniper woodlnds in the cold desert of the Intermountin West occupy over 44.6 million cres (Miller nd Tusch 21). These woodlnds re commonly ssocited with sgerush communities forming mosic of shru-steppe nd woodlnd cross the region. Numerous studies hve documented the recent expnsion (since the lte 18 s) of these woodlnds tht hs resulted in the replcement of shru-steppe communities. Recent dete hs chllenged the degree of expnsion in terms of percent of new res occupied y trees nd the increse in totl popultion of piñon nd juniper since the lte 18 s. Vrious interest groups hve ecome concerned over the limited scientific evidence documenting the expnsion of these conifers t rod scle (in other words, lndscpes or cross entire woodlnds) in the Intermountin Region. The fer of mny groups is historic woodlnds tht occupied lndscpes prior to Eursin settlement in the lte 18 s re eing urned, cut, nd chined in the nme of restortion. To evlute the mgnitude of expnsion on regionl level we evluted six woodlnds from their lower to upper elevtionl oundries in four different ecologicl provinces (Miller et l. 28). In this report we summrize our findings of woodlnd expnsion in the Owyhee Mountins nd discuss our preliminry findings from n ongoing study documenting chnges in plnt composition, structure, iomss, nd fuel lods with incresing tree dominnce. Specific questions ddressed in this report re: 1. Wht ws the density nd sptil extent of trees prior to 185? 2. Wht ws the chronologicl sequence of tree estlishment nd rtes of expnsion into shru steppe communities during the pst 15 yers? 3. Wht is the current successionl stte of woodlnd development (Phse I erly, II mid, III lte successionl)? 4. How do plnt cover, structure, nd iomss chnge in reltion to woodlnd succession (Phse I, II, nd III)? STUDY AREA The study res re locted on Juniper nd South Mountin in the Owyhee Mountin Rnge in Owyhee County, Idho nd re considered prt of the Humoldt Ecologicl Province (Fig. 1). The geomorphology of this re is chrcterized s n uplifted region with doming nd fult locking common. The Owyhee Mountins re predominntly comprised of grnite; however, most of the uplnds re overlin y rhyolites nd welded tuffs with silicic volcnic flows, sh deposits, nd wind-lown loess. Topogrphic chrcteristics of this re include mountins dissected y deep cnyons, rocky tlelnds, nd rolling plins rnging in elevtion from 3,936 nd 7,79 ft. 54

61 Climte cross the Owyhee Mountins is chrcteristic of the northern Gret Bsin in tht it is cool nd semirid. Men nnul precipittion within the juniper elts vries etween 12 inches t lower elevtions incresing to 16 inches t higher elevtions. The mjority of the nnul precipittion is received s snow in Novemer, Decemer, nd Jnury nd s rin Mrch through June. Averge tempertures vry from 2.2 o F in Jnury to 94.1 o F in July. The growing seson vries from 9 to 12 dys. Soils rnge from shllow rock outcrops to modertely deep grvelly, sndy, or silt loms. Predominnt soil tx re Aridisols, Entisols, Alfisols, Inceptisols, nd Mollisols tht occur in comintion with mesic nd frigid soil temperture regimes nd xeric nd ridic soil moisture regimes. The Ntionl Resources Conservtion Service hs descried the re s potentil nturl vegettion s sgerush km Figure 1. Mp of the study loctions on South Mountin (north trnsect) nd Juniper Mountin (south trnsect) in southwest Idho. Three circulr plots were plced pproximtely every.3 miles long 3 prllel trnsects spced.3 miles prt; plot loctions were djusted to fit within uniform stnd t lest 1.25 cres in size with uniform chrcteristics (e.g. spect, topogrphy, soil, nd vegettion). 55

62 grsslnd. Predominnt vegettion in the re is western juniper, mountin ig nd low sgerush, Idho fescue, lueunch whetgrss, western needlegrss, Thurer s needlegrss, nd Snderg luegrss. METHODS To gin lndscpe scle perspective of oth the sptil expnsion nd incresing density of juniper, we estlished two trnsects ech pproximtely 1 miles long cross two woodlnds on Juniper nd South Mountin. Ech trnsect ws locted long n elevtionl grdient tht extended from the lower to upper oundries of ech woodlnd. Across the two trnsects we smpled tree ge structure nd density. Expnsion of post-settlement woodlnds ws determined y ging (coring nd counting the rings) of the three lrgest trees with postsettlement morphologicl chrcteristics. This enled us to estimte when the first postsettlement trees estlished on the plot. Tree density ws mesured y counting live nd ded trees in 158,.2- to.7-cre plots (plot size vried with tree density). Stnd density mesurements included presence, sence, nd density of trees estlishing prior to nd fter 185, stnding ded, stumps, nd logs. A complete ge structure of trees ws mesured on Juniper Mountin y ging ll trees within the plots. In n ongoing study, ner Juniper Mountin we re mesuring overstory nd understory structure (cover nd density) nd iomss in 45,.25- cre plots. Figure 2. Proportion of woodlnds in four successionl sttes; Phse I = trees present ut shrus nd grsses dominte the site, Phse II = trees co-dominte the site with shru nd grsses, Phse III = trees dominte the site nd shrus nd grsses hve declined, nd OG = stnds with > 75% of the trees older thn 15 yers. 56

63 Presettlement Western Juniper Stnds RESULTS AND DISCUSSION Prior to 185, 12% nd 7 % of the lndscpe in Juniper Mountin nd South Mountin, respectively, were occupied y juniper woodlnd (Fig. 2). The remining 88 to 93% were dominted y shru-steppe nd grsslnds with n intermingling of scttered western juniper. Within these shru-steppe nd grsslnd communities 48 nd 67% on Juniper nd South Mountin, respectively were occupied y low density of scttered juniper trees prior to 185 (Fig. 3). Of the current popultion of trees greter thn 3 ft tll, 5 nd 1% estlished prior to 185 (Fig. 3). Both density nd frequency of occurrence of western juniper prior to 185 were greter cross the two Idho woodlnds compred to woodlnds mesured in southestern Oregon where pre-185 trees occurred in less thn 3% of the stnds mesure nd 2% or less of the current popultion of trees (Johnson nd Miller 27). Figure 3. The proportion of () mixed ge (contined t lest on tree > 15 yers old in.7 cre plot) nd post settlement ge stnds (trees < 15 yers); () percent of the totl tree popultion > 3 ft tll tht were presettlement (> 15 yers old) nd post-settlement (<5 yers old). 57

64 % Trees Estlished Averge tree density 217 trees/c Figure 4. Current men juniper density nd decdl estlishment on Juniper Mountin, Idho. Pttern of Expnsion nd Estlishment On Juniper Mountin where we did the intensive ge structure smpling, current density of trees is 217/cre. Since 185, tree densities hve incresed more thn 1 fold. There ws slight increse in the rte of estlishment in the mid 18s, which then incresed rpidly during the lte 18s nd erly 19s (Fig. 4). The sudden decrese in tree estlishment in the pst three decdes is lrgely result of the lrge proportion of stnds tht re closed or pproching closure (lte Phse II nd Phse III). Competition mong overstory trees reduces seed crops nd tree seedling estlishment. The rte of tree expnsion into treeless shru-steppe communities peked etween 188 nd 193 (Fig. 5). The decline is result of shrinking proportion of the lndscpe without trees. Tree estlishment (numer of trees estlishing/yer) rtes incresed with elevtion nd shift from southerly to northerly spects (Fig. 6). Currently over hlf of the stnds mesured on oth Juniper nd South Mountins re in Phse II nd III with third or less in Phse I (Fig. 2). Overstory-Understory Reltionships Mny of the closed stnds tody shifted from Phse II to Phse III in the mid 195s. This is sed on shrp decrese in the reltive nnul growth rtes in the 195s, which continue to remin low compred tree growth rtes in Phse I stnds (Fig. 7). The decline is proly cused y intr-specific competition mong trees, result of limited soil resources. As soil nutrients nd wter ecome incresingly limited, the undnce of understory vegettion declines. The reltionship etween understory (shrus nd herceous plnts) nd overstory cover (trees) shown in Figure 8 is for mountin ig sgerush/idho fescue plnt ssocition ner Juniper Mountin. The mximum juniper cover mesured cross 31,.25 c 58

65 Decde South Mt, ID Juniper Mountin, ID % of Historic Sgerush Communities Invded/decde Figure 5. The proportion of decdl encrochment of juniper etween 186 nd 2 into treeless (no evidence of presettlement trees) sgerush-steppe communities. plots pproched 7% on Juniper Mountin. Similr vlues hve een reported y Miller et l. (2) for this plnt ssocition in southestern Oregon nd northestern Cliforni. Vrition of understory cover within phses of woodlnd development is prtilly result of different soil chrcteristics, especilly depth to restrictive lyer. However, the grph illustrtes tht shift from Phse I to II occurs t out ¼ of mximum potentil juniper cover (pproximtely 15% tree cover). The shift from Phse II to III occurs t out one-hlf of mximum potentil cover (pproximtely 3% tree cover). Tree iomss in Phse I ws elow 9, ls/cre nd incresing to over 3, ls/cre in phse III (Fig. 8). ACKNOWLEDGEMENTS Both pst nd ongoing studies re funded nd supported y the Joint Fire Science Progrm nd Estern Oregon Agriculturl Reserch Center. REFERENCES Johnson, D.D., nd R.F. Miller. 26. Structure nd development of expnding western juniper woodlnds s influenced y two topogrphic vriles. Forest Ecology nd Mngement 229:7-15. Johnson, D.D., nd R.F. Miller. 28. Old-growth juniper: distriution, undnce, nd influence on post-settlement expnsion. Journl of Rnge Ecology nd Mngement 61:

66 Miller, R.F., nd R.J. Tusch. 21. The role of fire in pinyon nd juniper woodlnds: descriptive nlysis. Tll Timers. Pges 15-3, in K. Glley nd T. Wilson (eds.), Fire Conference 2: The First Ntionl Congress on Fire, Ecology, Prevention, nd Mngement. Invsive Species Workshop: The Role of Fire in the Control nd Spred of Invsive Species. Tll Timers Reserch Sttion, Tllhssee, Florid. Miller, R.F., J.D. Btes, T.J. Svejcr, F.B. Pierson, nd L.E. Eddlemn. 25. Biology, ecology, nd mngement of western juniper. Oregon Stte University Agriculturl Experiment Sttion Technicl Bulletin 152. Corvllis, Oregon. Miller, R.F., R.J. Tusch, D. Mcrthur, D.D. Johnson, nd S.C. Snderson. 28. Development of post settlement piñon-juniper woodlnds in the Intermountin West: regionl perspective. USDA Forest Service Reserch Pper Report RMRS-RP-69. Rte of tree estlishment trees/c Elevtion (ft) 59 South 525 North As pect Figure 6. Reltionship of tree estlishment rtes (trees/cre/yer) with elevtion nd site exposure in stnds ssocited with mountin ig sgerush. Site exposure shifts from northerly to southerly spect from left to right. 6

67 3.5 3 Reltive Growth Rte Phse III Phse I Yer Figure 7. Reltive growth rtes sed on tree ring widths for Phse I nd III. Reltive growth is typiclly slow during the first 15-2 yers of tree growth. The numer 1 is the reltive men ring width for composite of trees in Phse III. The y-xis is the reltive growth rte (or mgnitude) of growth compred to the men. To compre growth rtes etween Phse I nd III, the reltive growth rte for trees currently in Phse I ws sed on the men growth rte for the Phse III trees. Figure 8. Reltionship etween overstory juniper cover, totl tree iomss, nd totl understory (shrus nd herceous plnts) cover. Phse I = trees present ut shrus nd grsses dominte the site, Phse II = trees co-dominte the site with shrus nd grsses, Phse III = trees dominte the site nd shrus nd grsses hve declined. 61

68 Juniper Cutting nd Prescried Fire Comintions; South Mountin, Idho Jon Btes, Kirk Dvies, Roger Sheley, nd Ro Shrp INTRODUCTION Control of western juniper y urning or cutting hs een successfully used to reestlish shru/understory plnt communities in the northern Gret Bsin. Tree cutting, using chinsws, hs generlly een pplied to res tht hve fully developed woodlnds (Phse III) nd no longer possess the understory fuels to successfully crry fire. Woodlnds tht lck dequte fuels re those in mid- to lte successionl stges where juniper competition hs eliminted the shrus nd reduced understory production. In mny juniper control projects only portion of the trees need to e cut to increse surfce fuels so tht prescried fire cn remove remining live trees. Reducing the numer of trees cut could lower costs nd permit lrger creges to e treted. An ojective of the reserch ws to ssess wht level of preprtory cutting is required to eliminte remining juniper trees y prescried fire in the fll. The study lso evluted the effect of the tretments on post-fire vegettion dynmics nd effects of seeding for site recovery. METHODS Study sites were set up within the Juniper nd Cin Creek dringes on South Mountin, Idho (out 6 ft. elevtion). Two plnt community types were selected for tretment; western snowerry-mountin sgerush/idho fescue-western needlegrss (SNOWBERRY) nd mountin ig sgerush/lettermn s needlegrss (SAGE). Sites were dominted y postsettlement western juniper woodlnds (ll Phse III woodlnds). Phse I woodlnds contin trees ut shrus nd hers re the dominnt vegettion. In Phse II, trees re co-dominnt with shrus nd hers nd ll three vegettion lyers influence ecologicl processes. Phse III woodlnds re when juniper is the dominnt vegettion nd the primry plnt lyer influencing ecologicl processes. Juniper cover rnged etween 4-7% nd tree densities rnged from 1-3 trees per cre. Preprtory tree mnipultions were chinsw cutting 25%, 5%, nd 75% of the postsettlement trees in Octoer 22 (tretments were: SAGE 25, SAGE 5, SAGE 75; SNOWBERRY 25, SNOWBERRY 5, SNOWBERRY 75). Ech tretment plot ws 1.5 cres in size nd ws replicted 5 times (4 plots totl). Totl re used per community type ws 3 cres (6 cres totl). Cut trees were llowed to dry for one yer prior to fire ppliction. Prescried fires (strip hed fire) were pplied on Octoer 21-22, 23. Uncut/unurned woodlnds (CONTROL) were locted djcent to treted res. Smpling included mesurement of cover nd density of juniper, shrus, nd herceous species. Herceous species were lso mesured for iomss (26) nd diversity. One yer 62

69 of pre-tretment (22) nd three yers of post-tretment response (24-26) dt were collected. Seeding trils were conducted on smll portion of the study re. Six ntive species were seeded in monoculture t four rtes nd seeded in mixture of ll six species t four rtes. Non-seeded controls were estlished to compre untreted response with seeded plots. Ntive grsses were lueunch whetgrss, Idho fescue, Shermn ig luegrss. Fors were western yrrow, rrowlef lsmroot, nd wild lue flx. Seeding rtes were 15.6, 2.4, 25.4, or 31.1 l/cre of pure live seed. Juniper Removl RESULTS The prtil cut nd urn tretments were ll successful t removing remining live western juniper trees. On the SNOWBERRY type the fire killed 95-99% of remining live trees nd juniper cover ws reduced y 99%. On the SAGE type fires killed 85-1% of the remining live trees nd juniper cover ws reduced y 9-94%. Understory Dynmics Understory response did not differ mong the vrious cutting levels nd prescried fire pplictions within ech plnt community type. In oth communities, perennil unchgrss densities were modertely to severely reduced the first yer fter urning. However, y the third growing seson (26) fter fire, perennil grss densities were greter in the treted sites thn the CONTROL s result of lrge numers of grss seedlings. Herceous iomss ws greter in treted sites thn the CONTROL in 26 (Fig 1). On the SNOWBERRY type nnul for nd totl iomss were greter thn the CONTROL (Fig. 1A). On the SAGE type perennil unchgrss, perennil fors, nnul fors, nd totl iomss were greter thn the CONTROL (Fig. 1B). In the SAGE community type, cover nd density of perennil fors, nnul fors, nd totl herceous were greter in the urned tretments thn the CONTROL (Fig 2). For diversity incresed y 3%. Weeds slowly incresed ut were not expected to dominte either plnt community type. Chetgrss incresed on the SAGE type; however, ecuse of incresed estlishment of perennil grss seedlings chetgrss is not expected to ecome dominnt. Bre ground did not increse s result of the fire; however, juniper litter ws reduced fter urning (Fig. 3). In the SNOWBERRY community type, cover nd density of nnul fors nd totl herceous were greter in the urned tretments thn the CONTROL (Fig. 4). For diversity incresed y 1-22%. Bre ground ws greter in the treted plots thn the CONTROL (Fig. 5). Juniper litter ws reduced fter urning. Herceous litter incresed in the treted res nd ws greter thn the CONTROL in

70 Shru cover nd density hs not differed mong tretments for either community type. Sgerush nd itterrush remined present in the SAGE type ut densities were reduced y urning. Seeding Blueunch whetgrss, Idho fescue, Shermn ig luegrss, western yrrow, nd wild lue flx ll estlished successfully. Arrowlef lsmroot did not estlish successfully. The highest iomss production ws comintion seeding t 2.4 l/cre on the SAGE site nd 31.1 l/cre on the SNOWBERRY site. Seeding comintion of species resulted in moderte to high density of plnts nd optimized plnt diversity nd richness over seeding monocultures. ls c SNOWBERRY TYPE SNOW-CONTROL SNOW25 SNOW5 SNOW75 ls c PG RPG POBU Crex AG PF NNPF AF Totl SAGE TYPE SAGE-CONTROL SAGE25 SAGE5 Sge75 2 PG RPG POBU Crex AG PF NNPF AF Totl Plnt Functionl Group Figure 1. Biomss (l c -1 ) of the functionl group iomss in 26. Dt re in mens + one stndrd error. Significnt differences mong tretments for functionl groups re indicted y different lower cse letters. Functionl groups re; Perennil Bunchgrss (PG); Rhizomtous grsses (RPG); Bulous luegrss (Pou); Crex spp.; Annul Grsses (AG); Ntive Perennil For (PF); Non-Ntive Perennil For (NPF); Annul For (AF); nd Totl Herceous. 64

71 8 A. Perennil Grsses Sgerush Sites Cover % Cover % B. Po Spp. Cover (%) A. Breground SAGE Control SAGE 25 SAGE 5 SAGE 75 Cover % Cover % Cover % C. Perennil Fors D. Annul Fors E. Herceous Cover SAGE 25 SAGE 5 SAGE 75 SAGE Control Yer,,,,,,,,,, Figure 2. SAGE TYPE: Functionl group cover (%) for the tretments in for: (A) Perennil Grsses; (B) Bluegrss spp. (Bulous nd Snderg s); (C) Perennil Fors; (D) Annul Fors; nd (E) Totl Herceous. Dt re in mens + one stndrd error. Cut nd urn tretments did not differ ut ll re greter thn the Control for Perennil Fors, Annul Fors, nd Totl Herceous. Cover (%) Cover (%) B. Juniper Litter C. Herceous Litter, YEAR,,,,, Figure 3. Sgerush Sites: Ground cover (%) for the tretments in for: (A) Breground; (B) Juniper Litter; nd (C) Her. Litter. Dt re in mens + one stndrd error. Juniper litter ws reduced y urning. 65

72 % COVER % COVER % COVER % COVER % COVER A. Perennil Grsses B. Po spp. C. Perennil Fors D. Annul Fors SNOWBERRY Control SNOWBERRY 25 SNOWBERRY 5 SNOWBERRY 75 5 E. Herceous Cover YEAR c c,,,, Figure 4. Snowerry Sites: Functionl group cover (%) for the tretments in for: (A) Perennil Grsses; (B) Bluegrss spp. (Bulous nd Snderg s); (C) Perennil Fors; (D) Annul Fors; nd (E) Totl Herceous. Dt re in mens + one stndrd error. Cut nd urn tretments did not differ ut they ll re greter thn the Control for Annul Fors nd Totl Herceous. Cover (%) Cover (%) Cover (%) Snowerry Sites B. Juniper Litter c c, C. Herceous Litter SNOWBERRY 25 SNOWBERRY 5 SNOWBERRY 75 SNOWBERRY Control, A. Bre ground & Rock c c,,,,,, 26 Fig 5. Snowerry Sites: Ground cover (%) for the tretments in for: (A) Bre ground; (B) Juniper Litter; nd (C) Her. Litter. Dt re in mens + one stndrd error. Bre ground ws incresed y the fire primrily ecuse of the lrge reduction in juniper litter. Herceous litter incresed in 26 in the treted res. 66

73 DISCUSSION nd CONCLUSIONS Juniper Control The results indicted tht cutting only 25% of mture trees in communities dominted y western juniper (Phse III, juniper cover 4-7%) ws sufficient to remove the mjority of remining live trees in stnds with fll prescried fire. Cutting more thn 25% of the trees ws excessive when rodcst urning ws pplied with wether conditions typiclly encountered with fll prescried fire. Burning ws eqully effective on slopes (SNOWBERRY nd SAGE type 1-5% slopes) nd on flt ground (SNOWBERRY type). Crowning or cnopy fires were mintined in some djcent uncut woodlnds with little understory. Cutting levels could proly e reduced in the res with greter thn 6% juniper cover (e.g. SNOWBERRY type, out 3 stems per cre) nd still chieve sufficient kill on remining live western juniper. Cutting 15-25% (out 5-75 stems cut per cre) of the trees or strip cutting should e considered when fll urning thicker stnds of western juniper. For treting western juniper on lrge scle cutting-prescried fire comintions re useful method of tree control tht should reduce tretment costs. Old Juniper Trees A portion of the old western juniper trees growing on rocky outcrops ove the tretment res were killed y the fire. These trees hd survived historicl (pre-settlement) fire events. Cut trees when urned re oviously providing the necessry het nd flme lengths to kill the older trees. Options to increse survivl of the older trees would e to physiclly remove cut western juniper fuels djcent to old trees or not cutting postsettlement trees growing ner old trees until fter fll fire is pplied to surrounding res. The invsive trees could then e cut nd winter urned. Understory Dynmics The results present erly successionl dynmics fter cut-nd-urn tretments. These tretments produced severe impcts to the understory nd it is cler tht understory recovery will tke longer thn 3 yers. On the SAGE type, hot spots such s round tree oles nd under cut trees re expected to permit chetgrss to dominnt these loctions for severl yers. However, the potentil for plnt community recovery is high ecuse of the sites elevtion nd precipittion zone, nd present herceous composition. As this point it ppers tht oth the SAGE nd SNOWBERRY types will recover with primrily ntive perennil vegettion. When prescriing these cut-nd-fll urn tretments in Phse III woodlnds it cn e initilly e expected to stimulte perennil nd/or nnul fors; perennil unchgrsses will e modertely to severely reduced. If chetgrss or medushed is present there is potentil for these species to tke over site, thus, mngement should e cutious when pplying these tretments. 67

74 Seeding To speed site recovery fter fire seeding should e considered nd livestock grzing should e crefully mnged. On oth community types seeding trils were highly successful t speeding perennil unchgrss response nd were oserved to reduce erosion. Other Mngement Considertions For mngement purposes it is most importnt to increse perennil grss cover/densities s this functionl group hs the most vlue t reducing erosion nd minimizing weed invsion in Gret Bsin plnt communities. Until ground cover is reestlished (5-8 yers) urned res cn experience significnt runoff with moderte to hevy rin showers. Becuse of the high mortlity of perennil unchgrsses in response to fire, grzing rest or deferrls will likely e necessry fter fire tretments. Grzing mngement of urned res should e flexile; with the overll ojective of incresing perennil grss cover/densities to minimum of 4-6 plnts/yrd 2. Both sites re cple of supporting higher perennil grss densities (1-2 plnts/yrd 2 ). With or without seeding, urned res should proly e rested the first nd possily second yer fter fire to mximize unchgrss seed crop nd estlishment. Deferring grzing until fter seed shtter the second through fourth growing seson would increse grss seed production nd estlishment. Bsed on the results here nd in our other studies it will tke longer thn 2 yers, possily s mny s 8 yers, for unch grsses to fully recover. Erly seson grzing (prior to grss oot stge) or deferring grzing until fter seed shtter should proly e considered in lter yers fter fire (yers 3-8). Winter urning of cut trees should e considered to limit mortlity of herceous perennils nd speed recovery (Btes et l. 27). Cutting levels would hve to greter (6-8%) to kill enough trees to elicit n herceous/shru response. Burning should e done when soil nd ground litters re t field cpcity nd frozen (Nov.-Mrch). ACKNOWLEDGEMENTS Mny thnks re extended to Bill nd Tim Lowry (Jordn Vlley, Oregon) nd Idho Deprtment of Stte Lnds for providing lnd for conducting the study. Mike nd Jenie Stnford permitted ccess through their property nd provided logisticl help. The success of the project owes much to the mny student summer rnge technicins who ssisted in the collection of field dt nd to ARS rnge technicins ssisting in the fire pplictions. REFERENCES Btes, J., R. Miller, T. Svejcr, K. Dvies, F. Pierson, S. Hrdegree. 27. Western Juniper Control Studies: EOARC Reserch Progress Report. Estern Oregon Agriculturl Reserch Center, Sttion Report, Burns. 57 p. 68

75 Hydrologic Response to Western Juniper Control Tim L. Deoodt, M.P. Fisher, J.C. Buckhouse, nd John Swnson SUMMARY Western juniper (Juniperus occidentlis) hs een ssocited with incresed soil loss nd reduced infiltrtion resulting in the loss of ntive herceous plnt communities nd the ird nd niml species tht rely on them. USDA Forest Service inventory nlysis indictes tht since 1934 western juniper s dominnce on estern Oregon s rngelnds hs grown from 1.5 million to over 6 million cres. In 1993, pired wtershed study ws initited in the Cmp Creek dringe, triutry of the Crooked River of centrl Oregon, to evlute the impcts of cutting western juniper on the hydrologic function of site. The study involved pired wtershed pproch using wtersheds of pproximtely 24 cres ech to evlute chnges in system s wter udget following the reduction of western juniper. Wter udget is mesured in terms of inputs (precipittion) nd outputs (soil moisture, runoff, groundwter rechrge nd evpotrnspirtion). Wtershed impcts include chnges in wter udget s well s vegettion composition nd cover chnges nd ltered erosion rtes. Previous monitoring studies hve een limited in their scope to wter qulity impcts (soil erosion) nd infiltrtion rtes nd vegettive responses following juniper control. In 25, following 12 yers of pretretment monitoring in two wtersheds (Mys nd Jensen) ll post post-settlement ged juniper (< 14 yers of ge) were cut from the tretment wtershed (Mys) (Fig. 1) Hydrologic responses including chnges in depth to ground wter, spring flow, chnnel flow, nd soil moisture were ssessed. Vegettive cover chnges were mesured. Anlysis indicted tht juniper reduction incresed lte seson spring flow, incresed dys of recorded ground wter nd incresed the reltive vilility of soil moisture t the deeper soil depths. Ephemerl chnnel flow nd chnnel morphology did not show predictle trend following 2 yers of post-tretment mesurements. Precipittion received from Octoer through My ccounts for 7 percent of the nnul precipittion nd directly impcts ctul wter yields. INTRODUCTION AND OBJECTIVES Western juniper s dominnce in estern Oregon hs incresed 5 fold since 1934 (42, cres in 1934 nd 2,2, cres in 1999). Bsed on wter use models for individul trees, the U.S. Forest Service estimtes tht mture western juniper tree densities, rnging from 9 to 35 trees per cre, re cple of utilizing ll of the ville soil moisture on given site. Reserch hs shown tht soil loss from sites with higher thn the nturl vrition of western juniper cover is n order of mgnitude greter thn similr sites tht re still within their nturl rnge of vrition. Wter quntity nd timing re the primry fctors eing monitored with this project. The project involves the use of pired wtershed study. The project consisted of the tretment (cutting juniper) of one of the pired wtersheds totling pproximtely 25 cres with the other wtershed serving s the untreted control. The Prineville Bureu of Lnd 69

76 Mngement (BLM) District cut pproximtely 2 cres of western juniper in the Mys wtershed. The cutting ws strted in Octoer, 25 nd ws completed in April, 26. The pired wtershed project is locted pproximtely 6 miles southest of Prineville, Oregon. In 1993, two wtersheds (Mys nd Jensen) were identified in the Cmp Creek dringe. Ech wtershed is locted t the hedwters of ech dringe. The elevtion of the project re rnges from 4,5-5 feet with n verge nnul precipittion of 13 inches. The historic vegettion type ws mountin ig sgerush / Idho fescue. The site is currently dominted y western juniper with sprse understory of shllow rooted perennil grsses nd fors. Since 1994, the two wtersheds hve een monitored for similrities nd differences. Project Ojectives Evlute hydrologic chnges following the cutting of post-europen ged juniper (trees estlished since mid-18 s). Evlute chnges in hill-slope erosion nd chnnel morphology following the cutting of post-settlement juniper. Evlute chnges in plnt community composition following the cutting of postsettlement juniper. The mjority of the two wtersheds re comprised of pulic lnd, dministered y the Prineville District, BLM (75% Mys, 86% Jensen). The remining portions of ech wtershed re owned y the Htfield High Desert Rnch. The BLM, in coopertion with Crook County Soil nd Wter Conservtion District (SWCD), the permittee (Htfield s), nd Oregon Stte University ()SU) Deprtment of Rngelnd Ecology nd Mngement, identified the pired wtersheds s n re of interest ecuse of the opportunities the study provided to monitor chnges in wter yields s result of juniper control. METHODS Estlishment of the study egn in Ech wtershed ws delineted y the loction of continuous recording flume plced in the chnnel t the lowest point of ech wtershed. Flow ws mesured nd recorded with the id of dt logger. Precipittion inputs were first mesured with the use of Belfort Universl Rin Guge nd in 24, wether sttion ws dded to ech wtershed to record ir temperture, precipittion, wind speed nd direction, solr rdition, lef wetness, reltive humidity nd snow ccumultion. Permnent vegettive trnsects were estlished in ech wtershed nd locted y spect. In ech wtershed, 8 1 ft. trnsects were locted, 2 per spect nd dt were collected in 1995, 23, 25, nd 27. Bsl cover of grsses nd cnopy cover of fors, shrus, nd trees were recorded. 7

77 Figure 1. Aeril photogrph of project re 6 miles southest of Prineville, Oregon 71

78 Permnent chnnel cross-sections nd hill-slope erosion plots were locted in ech wtershed. Twenty-five cross-sections nd twelve sets of hill-slope trnsects hve een mesured once or twice yer. In 24, dditionl monitoring ws dded to the wtersheds (Fig. 2). Within ech wtershed, spring ws improved nd flow mesured. Six peizometers (shllow wells) were plced cross the vlley ottoms of ech wtershed ner the flume loction. Soil moisture nd soil temperture proes were instlled t two loctions within ech wtershed nd plced t multiple soil depths. All monitoring of wether, spring flow, chnnel flow, soil moisture nd depth to wter ws done through stellite uplinks nd dt re ville for viewing on the we site: Figure 2. Loction of monitoring sttions in Jensen nd Mys wtersheds. Spring Flow RESULTS The figure elow nd Tle 1 illustrtes the differences in output etween the two springs nd the differences etween yers. Spring flow is dependent on timing, type, nd mount of precipittion. Bse flow is lest likely to e influenced y recent precipittion event or snow melt period nd is equivlent to lte seson flow. Lte seson flow is defined s the period etween July nd Novemer. 72

79 Gllons per Minute Lte Seson Spring Flow nd Monthly Precipittion 9/1/3 1/1/4 5/1/4 9/1/4 1/1/5 5/1/5 9/1/5 1/1/6 5/1/6 9/1/6 1/1/7 5/1/7 9/1/7 25 Mys (treted) Jensen (control) Monthly Precipittion Inches of Precipittion 9/1/3 1/1/4 5/1/4 9/1/4 1/1/5 5/1/5 9/1/5 1/1/6 5/1/6 9/1/6 1/1/7 5/1/7 9/1/7 Dte -1 Tle 1. T-Test for Spring Flow Dt, lowest flow recorded (GPM). Dt shows results for comprisons of lte seson flow (lowest flow recorded) etween the two wtersheds nd the pre nd post tretment yers. The one tiled P-vlue is significnt t lph =.5**. Tretment Yer Wtershed Difference Men Vrince Mys Jensen Pre Pre Post Post Difference Stndrd error = ; t-test= , One tiled P-vlue ** Tle 2. Comprison of Averge numer of dys of well wter for the wtersheds. Pre nd post tretment yers consist of 2 yers ech. Wtershed Well Pretretment Post tretment Difference Mys Jensen

80 Peizometer Wells Well dt provides insight to the timing or vilility of susurfce wter. The length of ground wter vilility could e n indictor of wtershed function (Tle 2). Increses in length would indicte n improved hydrologic condition (see figure elow). A review of the dt indictes tht chnges in the verge numer of dys in which wter ws recorded in the wells incresed in Mys wtershed s result of cutting the trees. Using Wilcoxon rnk test the wells in Mys post-tretment, recorded greter increse in the numer of dys tht wter ws recorded when compred to the control wtershed (Jensen). Dys of recorded Well Wter 2nd yer fter tretment Pretretment Averge 2 yr.ve Post Tretment Difference Mys Wells Jensen Soil Moisture Oserving the lowest redings of the yer within ech wtershed illustrted the mount of wter svings tht ws crried over from one yer to the next. Evluting the chnge in wter svings over yers helps us see if tht chnge ws ssocited only with precipittion, or if increses might hve een due to the lck of deep-rooted vegettion (the cutting of the juniper). If it ws due to the removl of deep rooted vegettion, then excess soil moisture could move through the soil profile nd into su-surfce wter storge nd flow. Individul proe redings were verged y loction within the soil profile nd y site for ech wtershed (Figures next pge). Anlysis showed tht the oserved increse ws significnt for; the difference etween 26 nd 25, the verge increse difference of comined, nd 25 when compring Mys with Jensen. Tle 3 shows the results of this test for the comined yers compred to

81 5 Mys Wtershed Soil Moisture - Lowest reding of the yer Bottom Profile Percent Moisture Proe Lower Site Upper Site Averge 5 Jensen Wtershed Soil Moisture - Lowest reding of the yer Bottom Profile Percent Moisture Proe Lower Site Upper Site Averge Tle 3. Significnce of end of yer soil moisture ccumultion post vs. pre tretment. Yer Profile Loction P-vlue Difference 26-7 vs. 5 Bottom (.27 in).12* 26-7 vs. 5 Middle (.18 in) vs. 5 Top (.7 in)

82 Chnnel Flow Chnnel flow in the two wtersheds is ephemerl. These chnnels hve flow only during periods of snow melt nd extreme summer thunderstorm ctivity. Comprisons of ephemerl chnnel flows or dys of flow did not show reltionship to the tretment. In most yers, recorded chnnel flow occurs during the spring nd erly summer months. In 1996 nd 24, totl nnul dys of flow were greter thn dys of springtime chnnel flow, result of lte summer thunderstorms nd erly fll rin. In ll yers ut one, Mys flowed longer thn Jensen. Only in 1998 did Jensen flow longer when compred to Mys. In 27, while length of flow ws greter in Mys, Jensen s flow s mesured in ccumulted cuic feet per second ws greter thn Mys flow. Of specil note in the oservtion of these systems ws the winter of 26, following the cutting of juniper in Mys. The snow pck, which egn ccumulting in Decemer, 25 ws sttic t pproximtely 16 inches. Decemer nd erly Jnury rin events sturted the snow pck. As mentioned erlier, soil tempertures during this period did not drop elow 32 degrees F for either wtershed. Chnnel flow in Mys egn on Jnury 7, 26. Flow ws recorded through mid-june, 26. In contrst, flow in Jensen did not egin until April 1, 26 nd cesed to flow y erly My. During this period, ll oservtions for oth wtersheds indicted tht flow ws generted exclusively from nk seepge nd tht no evidence of overlnd flow ws oserved for either wtershed. In contrst, during the winter of 27, very little snow pck ws ccumulted. Bre ground in oth wtersheds ccounted for 5 7% of the lndscpe, with snow ccumultion res mesuring less thn 6 inches. Soil tempertures in erly Ferury were pproximtely 22 o F. An erly Ferury storm produced rin on snow event. Flow ws recorded in oth wtersheds nd the mjority of chnnel flow originted s overlnd flow. Sediment movement ws oserved on the hill slopes nd in the chnnels nd sediment hd to e removed from oth flumes. The oservtions in 26 nd 27 illustrte the high vriility within these systems nd the difficulty in connecting chnnel flow dt to tretment effects, especilly during the first 2 yers following tretment. Chnnel morphology Chnnel morphology (the shpe of the chnnel) ws unique to ech of the two wtersheds t the time the study ws initited. The chnnel in Jensen cn e descried s eing generlly shllow, with less steep sides nd wider chnnel ottom. The chnnel could e chrcterized s U-shped with the chnnel ottom controlled y rock. The chnnel depth is rrely more thn 3 ft deep. This chnnel ppered to e influenced more y side-hill erosion processes s demonstrted y chnnel cross-sections eing completely silted in due to side-hill sediment movement. The chnnel in Mys cn e chrcterized s eing deeper nd V-shped with multiple hed cuts found long its length. This chnnel ottom ws not controlled y rock. Portions of the chnnel in Mys exceed 12 ft of depth. The chnnel in Mys lso tends to support 76

83 longer periods of flow through greter expnse of its length thn does the chnnel in Jensen. This chnnel ppered to e controlled more y in-chnnel processes (hed cutting). Time series nlysis demonstrted greter vrition of chnge in cross-sectionl res in the tretment versus the control wtershed. The chnnel dt from Mys tended to depict periodic, extreme soil movement events intermixed with periods of little to no soil movement, wheres, the chnnel dt from Jensen showed more consistent soil movement with fewer extremes. This vrition my e product of the two chnnels eing t different evolutionry stges reltive to ech other nd thus indicting tht chnnel recovery would e different for ech wtershed. By cknowledging these inherent differences within ech wtershed, we my expect potentilly different chnnel-forming processes. Long-term monitoring questions yet to e nswered include how ephemerl chnnel processes work following vegettion tretments, nd how recovery periods ssocited with vegettive tretments my differ sed on chnnel morphology, ssocited vegettive conditions, nd hydrologic processes. Elevtion (cm Mys # Chnnel Width (cm) top of section 1994 S 1996 F 1997 S 1997 F 1999 S 1999 F 2 S 2 F 21 S 21 F 22 S 22 F 23 S 24 S 25 S 25 F 26 S 26 F 27 S 27 F Digrm of chnnel morphologicl chnges over time ( ) using single cross-section Mys 21. The figure ove demonstrtes in cross-section the chnges in chnnel morphology tht hve occurred since 1994 for the Mys wtershed. Some chnnel cross sections show ggrdtions or ccumultion of sediments in the chnnel, trending upwrd towrds U- shped chnnel. Other cross sections show chnnel degrdtion or continued downwrd movement of the chnnel ottom, creting V-shped chnnel. 77

84 MANAGEMENT IMPLICATIONS A helthy, functioning wtershed is one tht cptures, stores, nd sfely releses the precipittion tht is delivered to the site. Lnd mngement decisions should include looking for wys to increse opportunities for precipittion to infiltrte into the soil profile, moving excess moisture into su-surfce storge nd ground wter, slowly relesing tht wter to minimize the risk of soil loss, nd stilizing chnnel eds nd nks. Others hve suggested tht there would e no wter yield increse s result of vegettion mnipultion (juniper cutting) in precipittion zones where nnul precipittion ws less thn 43 mm (17 inches). Any chnge to the wter udget would only yield n increse in soil moisture, improving herceous vegettive production. The 3-yer verge nnul precipittion t Brnes Sttion (USGS wether sttion) locted pproximtely 1 miles est of the study site is 3492 mm (13.8 inches). Precipittion over the lst 4 yers on the study site hs rnged from 2781 mm (1.9 in., 8 percent of verge) nd 4491 mm (17.7 in., 129 percent of norml). Both the high nd low precipittion yers occurred during the post-tretment phse of the study. A review of the dt collected over the course of the lst 13 yers indicted tht the cutting of post-settlement ged juniper hs chnged the wter lnce eqution. Anlysis of the first 2 yers following tretment hs shown tht spring flow, ground wter, nd soil moisture hve ll incresed when compred to pre-tretment levels. The comprisons of ephemerl chnnel flows did not show s cler trend (dt not presented here). This is likely ecuse ephemerl flows tend to contriute more to ground wter rther thn ground wter contriuting to chnnel flow. In the uplnds, mngement implictions suggest tht with juniper removl, herceous vegettion cn crete more uniform ground cover cross the hillslope. Reduced re ground results in incresed infiltrtion opportunity nd decresed soil erosion. Improved hydrologic function of the uplnds cn mintin site stility nd fertility. Within the riprin re, mngement implictions point to the opportunity to increse spring flow for livestock, wildlife, nd domestic use long with some mitigtion of wter diversion. Lte seson low flows often limit lnd mngement lterntives. Incresing flows y cutting juniper could prtilly offset this limittion. Chnges in ground wter my hve downstrem impcts such s dding to chnnel or perennil strem flows. By comining the uplnd nd riprin enefits of juniper removl, the system will egin to move towrd wtershed tht is functionl in its ility to cpture, store, nd sfely relese wter nd provide site tht is productive nd cple of eing mnged for sustinle use. 78

85 REFERENCES Fisher, M.P., T. Deoodt, J. Buckhouse. 28. Chnnel geomorphologicl chnges nd hillslope soil movement following juniper tretment on Cmp Creek pired wtershed study. Society of Rnge Mngement, 61st Annul Meeting, Louisville, Kentucky. Gedney, D.R., D.L. Azum, C.L. Bolsinger nd N. McKy Western juniper in estern Oregon. Generl Technicl Report PNW-GTR-464. USDA Forest Service Pcific Northwest Reserch Sttion, Portlnd Oregon. 53 p. Hiert, A.R Wter yield improvement potentil y vegettion mngement on western rngelnds. Wter Resources Bulletin 19: Lrsen, R.E Interception nd wter holding cpcity of western juniper. PhD. Disserttion. Oregon Stte University, Corvllis, OR. 172 p. 79

86 Runoff nd Erosion fter Cutting Western Juniper Frederick B. Pierson, Jon Btes, Tony Svejcr, nd Sturt Hrdegree INTRODUCTION We used rinfll nd rill simultion techniques to evlute infiltrtion, runoff, nd erosion on cut nd uncut western juniper tretments. Reserch from pinyon-juniper wtersheds in the southwest demonstrtes strong reltionship etween vegettion cover nd soil erosion y wind nd wter. The purpose of this study ws to quntify hydrologic chnges ssocited with vegettion recovery 1 yers fter western juniper control in estern Oregon. Specific ojectives were to mesure chnges in surfce runoff nd rill erosion s function of rinfll intensity nd to ssess surfce soil nd vegettion fctors tht re influencing hillslope hydrology nd erosion. METHODS The study site ws on Steens Mountin in southestern Oregon. Elevtion t the site is 1575 m nd spect is west fcing with 1% slope. The site ws dominted y postsettlement western juniper woodlnd (Phse III) Juniper cnopy cover verged 26.5% nd tree density verged 283 trees/h. Shrus were eliminted from the site. Herceous cover verged 5.5 %. Bre ground nd rock in the interspce ws out 95%. Tretments consisted of removing juniper y cutting nd llowing the understory vegettion to recover for 1 growing sesons nd n uncut juniper woodlnd control. Eight 2-c locks were estlished. All trees on hlf of ech lock were cut in Simultions were pplied to eight cut plots nd eight woodlnd plots. Surfce hydrology nd understory vegettion response vriles were compred etween cut nd uncut juniper woodlnds. Oservtion indicted tht most runoff moved through interspce res: therefore, study plots were plced in interspces etween cut or uncut trees. Simulted rinfll ws pplied t trget rte of 2 in. hr -1, for 1 hour, to 37.5 yd -2 plots using eight sttionry sprinklers in June 21. Runoff nd sediment were collected during the simultion period. One hour following the rinfll simultion, flow regultor ws used to mesure runoff volume, sediment concentrtion, nd flow velocity in rills. Vegettion RESULTS Cutting junipers incresed totl vegettion cover (cnopy nd sl) nd litter cover (Tle 1). Cover ws out four times greter in the cut versus woodlnd tretment. Breground in woodlnd intercnopy zones ws 2-3 times higher thn the cut tretment. Rooting chrcteristics differed slightly etween tretments (Tle 2). In the juniper woodlnds, roots originted primrily from juniper nd in the cut tretment roots were primrily composed of perennil grsses. Root mss ws greter in the woodlnd, though, 8

87 root length nd root length density were greter in the cut tretment. Root length nd rootlength density dt indicte tht the cut tretment hd more fine roots thn the juniper woodlnd. This resulted in increses in roughness nd ggregte stility found in the cut tretment compred to the uncut woodlnd. Runoff Woodlnds rpidly produced lrge mounts of runoff while cut plots produced lmost no runoff (Figure 1, Tle 3). All woodlnd plots egn to runoff within 16 min following the strt of rinfll. Four plots egn to runoff fter only 2-4 min. Only two cut plots generted ny runoff during the 1-hourinfll simultion. One cut plot egn runoff t 31 min. nd the other t 43 min. The woodlnd plots were on verge 82% ponded (surfce sturted) while the cut plots were only 3% ponded. The ppliction of 2-yer return period thunderstorm equivlent on four juniper plots (5% of the woodlnd re) produced runoff, wheres no cut plots produced ny runoff. With the ppliction of 4-yer return period storm, seven juniper woodlnd plots (88% of the re) produced runoff; no cut tretment plots produced ny runoff. A 5-yer return period storm hd to e pplied efore two cut plots (25% of the cut re) egn to produce runoff wheres ll eight of the juniper plots produced n verge of 4 mm of runoff. Sediment Yield Sediment yield ws orders of mgnitude higher for the juniper woodlnd (1,52 l/cre) compred to the cut tretment (12.6 l/cre) (Fig. 1, Tle 3). The sediment to runoff rtio, mesure closely ssocited with soil erodiility, ws two times greter in the uncut woodlnd thn the cut tretment. This indictes tht soil prticles were more esily detched on woodlnd sites compred to res in the cut tretment. Tle 1. Ground cover (%) nd cnopy cover (%) in the intercnopy zones etween trees for juniper woodlnd nd juniper-removed tretments, Steens Mountin, Oregon, 21. Upper cse letters denote significnt tretment differences for individul ground cover components etween tretments. Lowercse letters denote significnt tretment differences for individul cnopy cover components. Cnopy Cover Juniper Woodlnd Juniper Removed Perennil Grss Annul Grss Perennil For Annul For Shru Vegettion Totl Litter Rock Bre Ground

88 Rill Dynmics Rill dischrge ws 3 to 7 times higher for the juniper woodlnd compred to the cut tretment for ll inflow rtes tested (Tle 4, Fig. 2). Sediment to runoff rtios were significntly higher for the juniper plots, indicting higher rill erosion compred to the cut plots. Rills in the cut res remined in more of trnsport-limited stte due to low rill dischrge rtes. The numer of rills ws nerly 5% greter nd the width of flow within ech flow-pth ws higher in the juniper woodlnd compred to the cut res. Wter velocity ws twice s high in the juniper plots. Tle 2. Hillslope chrcteristics for juniper woodlnd nd juniper removed tretments, Steens Mountin, Oregon, 21. Lower cse letters denote significnt tretment differences. Juniper Woodlnd Juniper Removed Slope (%) Rndom Roughness (m) Bulk Density -3 cm (g cm -3 ) Bulk Density 3-6 cm (g cm -3 ) Snd (%) Silt (%) Cly (%) Orgnic Cron (%) Aggregte Stility (%) Root Mss (g m -3 ) Root Length (cm) Tle 3. Comprison of cumultive runoff nd sediment yield etween juniper woodlnd nd juniper removed tretments for different return period storms, Steens Mountin, Oregon. Upper cse letters denote significnt differences etween tretments for runoff. Lowercse letters denote significnt differences for sediment yield. Time (min) Rinf ll (mm) Storm Return Period (y) Juniper Woodlnd Runoff (mm) Juniper Removed Sediment Yield (l c -1 ) Juniper Woodlnd Juniper Removed A.B A.B A.B A.96B

89 Cumultive Runoff (mm) Juniper Woodlnd Juniper Removed A y storm 5-y storm B Cumultive Sedement Yield (kg h -1 ) Time (min) Figure 1. Averge cumultive runoff (A) nd sediment yield (B) for juniper woodlnd nd juniper removed tretments (n=8), Steens Mountin, Oregon. Rinfll ws pplied t 2 inches/hr (1 yer storm event). Other storm events re shown on the grphs. 83

90 Tle 4. Rill flow chrcteristics y rill inflow rte for juniper woodlnd nd juniper removed tretments, Steens Mountin, Oregon, 21. Juniper Woodlnd Juniper Removed Inflow Rte (l min -1 ) Cumultive Inflow (L) Cumultive dischrge (L) 53.3* 154.3* 289.9* Cumultive sediment (g) 114.2* 368.5* 626.8* Sediment/Runoff (g L -1 ) * Numer of flow pths * Flow velocity (m s -1 ) * Flow depth (mm) Flow pth width (m) Totl flow width (m) * Tretment differences re significnt for ssocited inflow rte. CONCLUSIONS This study highlights the importnce of mintining understory vegettion nd litter cover when mnging western-juniper encrochment. Mngement prctices tht mintin dequte ground cover reduces soil loss nd retins site productivity. The hydrologic impcts of western-juniper in this study re consistent with studies tht hve linked chnges in infiltrtion, runoff, nd erosion to declines in understory vegettion nd surfce litter tht result in lrger, more inter-connected res of re ground. Lrge ptches of inter-connected re ground provide etter opportunity for runoff to concentrte into rills with high flow velocity, high erosive force, nd sediment trnsport cpcity. The high rill erosion rtes found in untreted juniper plots in this study were result of the increse in velocity of wter moving long greter numer of flow pths. Less ground cover nd incresed re ground in the juniper woodlnd provided less resistnce to wter moving over the soil surfce. Overlnd flow could then pick up more speed nd thus, energy for detchment nd trnsport of soil prticles in the flow pths. This coupled with significntly lower infiltrtion cpcity nd ggregte stility in the juniper woodlnd resulted in greter rill nd interrill dischrge rtes nd sediment concentrtions. Cutting the juniper nd llowing the site to recover for 1-yer period ws very successful t restoring the site to hydrologiclly stle condition. Surfce soil cover ws restored nd infiltrtion cpcity incresed sufficiently to protect the site from even lrge thunderstorms. When runoff ws generted in the cut res, the improved surfce cover conditions reduced the mount nd velocity of overlnd flow, therey drmticlly reducing rill erosion rtes. 84

91 12 1 Juniper Woodlnd Juniper Removed Rill Runoff Rte (L min -1 ) Rill Sediment Concentrtion (g L -1 ) Rill Inflow Rte (L m in -1 ) Figure 2. Averge rill dischrge rte (A) nd sediment concentrtion (B) y rill inflow rte (in liters) for juniper woodlnd nd juniper removed tretments (n=8) on Steens Mountin, Oregon, 21. Vlues for the sme rill inflow rte with different letters re significntly different (p<.5). Runoff nd sediment concentrtion re ll much greter in the woodlnd compred to the cut tretment. 85

92 Restortion of Quking Aspen Woodlnds Invded y Western Juniper Jon D. Btes, Rick Miller, nd Kirk W. Dvies INTRODUCTION Quking spen woodlnds re importnt plnt communities in the interior mountins of the western United Sttes. Occupying reltively smll res within vst lndscpes, spen woodlnds provide essentil hitt for mny wildlife species nd contin high diversity of understory shru nd herceous species. Western juniper woodlnds re rpidly replcing lower elevtion (<68 ft) quking spen stnds throughout the northern Gret Bsin. Fire exclusion hs resulted in juniper encrochment or replcement of spen woodlnds the pst 1 yers. The purpose of this reserch ws to evlute two juniper control tretments for restoring spen stnds in estern Oregon using selective cutting nd prescried fire. The two juniper control tretments involved cutting one-third of mture juniper trees followed y 1) erly fll urning (FALL); or 2) erly spring urning (SPRING). Becuse of lck of fine fuels nd reltively high fuel moisture contents, selective cutting of juniper ws done to increse surfce fuels (-6 ft) to crry fire through the spen stnds, kill remining juniper, nd stimulte spen regenertion. Specific ojectives were to: 1) test the effectiveness of tretments t removing juniper from seedlings to mture trees, 2) mesure tretment effectiveness t stimulting spen recruitment, nd 3) evlute the response of shru nd herceous understories to tretment. METHODS The study site ws locted in Kiger Creek Cnyon on Steens Mountin, southestern Oregon. The two western juniper control tretments involved cutting one-third of the mture juniper trees followed y: 1) erly fll urning (FALL); or 2) erly spring urning (SPRING). Tretments were locted next to untreted woodlnds (CONTROL). Trees were cut in winter nd spring, 21. The FALL tretment ws urned in mid-octoer, 21. The SPRING tretment ws urned in mid-april, 22. Smpling included mesurement of cover nd density of juniper, spen, shrus, nd herceous species nd understory diversity. Sites were mesured in June-July 2 nd Cut nd Fll Burn RESULTS The FALL tretment ws severe-stnd replcement fire, resulting in greter plnt mortlity nd more open spces for coloniztion y new individuls when compred to the SPRING tretment. The greter disturnce in the FALL tretment fvored spen recruitment nd growth. Burning eliminted remining juniper trees nd seedlings (Figs. 1 86

93 5 Juniper Cover (%) CONTROL FALL SPRING YEAR Figure 1. Juniper cover in spen stnds prior (2) to nd fter tretments, Kiger Cnyon, Steens Mountin Oregon. Letters denote significnt differences mong tretments nd untreted Control. & 2) nd stimulted 6-fold increse in spen suckering (5,42 stems/cre) (Figs. 3 & 4), ut resulted in severe reduction in herceous cover nd loss of perennil unchgrsses. Herceous cover in FALL ws less thn the SPRING nd ws primrily composed of weedy nnuls (ntive nd non-ntive) (Fig. 5). In 26, chetgrss mde up nerly 6% of totl herceous cover. Cut nd Spring Burn The SPRING tretment ws less severe fire tht thinned the overstory nd resulted in sustntil increse in herceous cover nd diversity. Eighty percent of the mture juniper trees tht remined fter cutting were killed, however, 5% of juniper juveniles survived (juveniles exceed 3 trees/cre) (Fig 1 & 2). Aspen suckering in the SPRING tretment incresed 3.5-fold (2,985 stems/cre) y the fifth yer post-fire (26) (Figs. 3 & 4). The SPRING tretment hs prolonged spen site occupncy ut the presence of juniper will result in co-dominnce of the overstory y spen nd juniper within 3 yers. Herceous cover incresed 33%, no mortlity of unchgrsses occurred, nd the numer of species oserved incresed y 5% y the fifth yer fter fire (Fig. 5). It is estimted tht livestock forge incresed out 1-fold. Herceous composition ws 87

94 DoSucnopy Juniper (trees c -1 ) Dominnt Juniper (trees c -1 ) Juvenile Juniper (trees c -1 ) CONTROL FALL SPRING A B C Yer Figure 2. Juniper tree densities in spen stnds prior to (2) nd fter tretments, Kiger Cnyon, Steens Mountin Oregon; A) dominnt juniper; B) su-cnopy juniper; nd C) juvenile trees (< 3 ft). The CONTROL is greter thn the tretments for ll ctegories. Juvenile junipers re greter in the SPRING thn the FALL. primrily composed of ntive grsses nd fors. Perennil for diversity ws highest in the SPRING tretment. Cut nd Fll Burn CONCLUSIONS Cutting comined with fll fire ws the most effective method t removing remining juniper nd stimulting greter spen suckering. The effectiveness of the tretment t removing juniper indictes tht spen will dominte the overstory the next 8-1 yers. The cutting of 88

95 Dominnt nd Sucnopy Aspen (trees c -1 ) A CONTROL FALL SPRING B 6 Aspen Suckers (suckers c -1 ) Yer Figure 3. Aspen densities prior to nd fter tretments, Kiger Cnyon, Steens Mountin Oregon; A) dominnt nd sucnopy spen; B) spen suckers (< 2 in dimeter t 3 ft). The CONTROL ws greter thn the tretments for dominnt nd sucnopy spen until 26. In 26 mny spen suckers In FALL nd SPRING tretments egn to e ctegorized s sucnopy ecuse stem dimeters exceeded 2 inches. one-third of the overstory juniper ws more thn dequte to eliminte remining live junipers with FALL fire tretment. This suggests tht cutting levels could potentilly e reduced when comined with fll fire. Fll fire severely impcted the understory nd reseeding of herceous perennils should e considered. Cut trees increse het fluxes into soils nd elevte mortlity of perennil species. Ntive perennil fors nd grsses were lrgely eliminted with the fll fire. In these lower elevtion spen stnds, non-ntive weeds pper to e of concern in erly succession s they rpidly increse efore ntive perennils cn reestlish. Wht hs een surprising is stedy increse of chetgrss in the FALL tretment. Chetgrss is unlikely to persist s Kentucky luegrss tht survived the fire hs slowly incresed nd will likely reoccupy treted sites. 89

96 5 A Totl Aspen Cover (%) , Aspen Sucker Cover (%) B CONTROL FALL SPRING Aspen Sucnopy/Dominnt Cover (%) 3 C Yer Figure 4. Aspen cover prior to nd fter tretments, Kiger Cnyon, Steens Mountin Oregon; A) totl spen cover; B) spen sucker cover; nd C) dominnt nd sucnopy spen. Letters denote significnt differences mong SPRING nd FALL tretments nd untreted CONTROLS. 9

97 Breground nd Rock (%) Litter (%) Herceous Cover (%) A B C CONTROL FALL SPRING c Yer Figure 5. Ground cover prior to nd fter tretments, Kiger Cnyon, Steens Mountin Oregon; A) Breground; B) Litter; nd C) Herceous cover. Letters denote significnt differences mong SPRING nd FALL tretments nd untreted CONTROLS. c c c c Perennil Grss Cover (%) Perennil For Cover (%) Annul Grss Cover (%) Annul For Cover (%) Numer of Species 4 A CONTROL FALL 3 SPRING B C D E CONTROL FALL SPRING,,,,,, YEAR Figure 6. Herceous functionl group cover nd herceous species identified prior to nd fter tretments, Kiger Cnyon, Steens Mountin Oregon; A) Perennil Grsses; B) Perennil Fors; C) Chetgrss; D) Annul fors; E) Species numers. Letters denote significnt differences mong SPRING nd FALL tretments nd untreted CONTROLS. Perennil grsses nd fors nd species numers re ll gretest in the SPRING. Chetgrss mkes up out 25% of totl herceous cover in the FALL. Also of note is tht species numers hs een lowest in the FALL the pst 2 yers (25-26)., c, c c, 91

98 Cut nd Spring Burn This tretment cn e considered only temporry interruption of the development to juniper woodlnd. The gps creted y the cutting nd fire disturnce will provide juniper splings nd seedlings with the opportunity to reoccupy the SPRING sites. However, if the mngement ojective is to rpidly increse the herceous component nd modertely increse spen suckering, spring urning is recommended. Spring urning my lso e useful in spen communities where the understory is depleted nd mngers desire more rpid recovery of this vegettion group. With spring urning, follow-up mngement will e necessry to remove juniper tht re missed in initil tretments to prevent erly return nd domintion y juniper. Given growth rtes of juniper, these stnds could e re-dominted y juniper in out 6-8 yers. When sites re urned in spring (or winter) preprtory cutting levels should proly e incresed ove 5% to increse chnces of remove higher percentge of junipers, oth mture nd juvenile trees, y fire. This level of cutting would likely not impct the understory negtively when the site is urned s long s soils nd surfce litters re frozen nd or t field cpcity (litter in contct with the ground); nd herceous vegettion is lrgely dormnt. An dvntge of spring urning is tht the fire cn e confined to the tretment re without much risk of escpe. This tretment would e useful in other forested systems (e.g Ponderos Pine, other encroching conifer species) nd in stnds djcent to res of mngement concern (e.g. Mountin ig sgerush hitt, riprin zones, structures, residentil res etc.). For exmple, it my e desirle to protect res, prticulrly sgerush grsslnd, to void negtive impcts to wildlife dependent on these communities. ACKNOWLEDGEMENTS Thnks to the Bureu of Lnd Mngement-Burns District for providing the opportunity to conduct the study nd pplying the fll urn tretment. Specil recognition is for Jim Buchnn of Burns-BLM for his work on the project. Fred Otley nd fmily were most generous in providing use of their summer cin during smpling periods. Mny student summer rnge technicins ssisted in the collection of field dt nd ARS rnge technicins (Clire Poulson nd Lori Zeigenhgen) ssisted in the spring fire pplictions. REFERENCES Btes J.D., R. Miller, nd K. Dvies. 26. Restortion of spen invded y western juniper. Rnge Ecology nd Mngement 59: Wll, T. R.F. Miller, nd T.S. Svejcr. 21. Juniper encrochment into spen in the northwest Gret Bsin. Journl of Rnge Mngement 54:

99 A Generlized Model for Estimting Biomss nd Fuel Lods for Western Juniper Jime Rtchford, Brenn Sin, Andrew Tierney, Rick Miller, nd Pul Doescher INTRODUCTION Western juniper hs significntly expnded its rnge since the lte 18 s nd currently occupies 9 million cres in estern Oregon, southwestern Idho, nd long the northern order of Cliforni nd Nevd. The conversion from shru-steppe to western juniper woodlnd shifts ove-ground iomss from primrily one composed of shrus nd grsses to dominnce y woody vegettion. This shift in iomss lso entils mjor chnge in the undnce nd structure of ecosystem fuel lods. This shift in fuel lod rrngement nd composition proly decreses the potentil for fire ignition ecuse of lck of fine fuels. However, ecuse of the chnges in fuel lod chrcteristics, once woodlnds re ignited they urn with higher intensity with the potentil for more severe effects to residul understory vegettion nd soil resources. Quntifying the chnges in ove-round plnt iomss in invsive western juniper woodlnds cn provide lnd mngers nd reserchers etter understnding of plnt community nd lndscpe dynmics. In ddition, recent interest in hrvesting western juniper for commercil energy genertion requires method tht cn estimte tree iomss cross wtershed nd lnd mngement units. Procedures for determining iomss nd fuel lods in woodlnd systems re poorly developed nd cn e tedious nd expensive. Biomss studies hve produced llometric equtions tht cn ccurtely estimte nd inventory the iomss of western juniper t locl scle. Becuse pst iomss equtions re derived from limited numer of sites, it is unknown if these estimtes cn e used to scle up to lrger lnd res or lndscpes. Developing estimtes of juniper iomss t lrger scles is needed to quntify fuel chrcteristics nd potentil energy resources. The ojective of this study ws to develop llometric models of western juniper tht would estimte tree iomss t multiple scles, including individuls, stnds, or lndscpes. To do this we selected three widely seprted loctions where we evluted the reltionship mong different dimensionl mesures with ove ground dry-weight of western juniper. STUDY AREA We selected three sites tht were representtive of invsive western juniper woodlnds (Fig. 1). The predominte vegettion on these sites were western juniper, mountin ig sgerush, Idho fescue, nd Snderg luegrss. These sites were in phse II of the woodlnd succession where intrspecific competition is miniml, the overstory cnopy is still open nd the dominnt ntive understory vegettion is still intct. The potentil plnt ssocitions t ll sites were mountin ig sgerush/idho fescue lthough nnul precipittion nd soils vries mong the three study loctions. 93

100 Figure 1. Distriution of western juniper woodlnds nd the loctions of the three reserch plots. The most northern site ws locted ner Fort Rock, Oregon. It is considered to e in the Humoldt Ecologicl Province. Soils re well drined nd shllow to modertely deep. They re clyey, semetitic, frigid, shllow, Vitritorrndic Durixerolls. The men nnul precipittion vries etween 9-12 inches. Tempertures rnge from n verge minimum of 24 F in Jnury to n verge mximum of 86 F in July with n verge nnul temperture rnge of 45 to 55 F. The elevtion ws pproximtely 5,6 ft. The second site ws locted ner Lkeview, Oregon. It is lso considered to e in the Humoldt Ecologicl Province, ut is cooler nd wetter site thn the Fort Rock site. Soils re well drined nd modertely deep. They re fine, smectitic, frigid Vertic Plexerolls. The men nnul precipittion vries etween inches. The tempertures rnge from n verge minimum of 2 F in Jnury to n verge mximum of 84 F in July with n verge nnul temperture rnge of 45 to 47 F. The elevtion ws pproximtely 4,7 ft. The third site ws locted in the Modoc Ntionl Forest ner Tule Lke, Cliforni, nd is in the Klmth Ecologicl Province. Soils re well drined nd shllow to modertely deep. They re fine lomy to lomy, mixed, mesic, Lithic nd Pchic Argixerolls. Annul precipittion vries etween 16 2 inches. Averge nnul tempertures rnge from 43 to 45 F nd the elevtion is pproximtely 5, feet. 94

101 METHODS At ech ecologicl site one, five-cre plot ws estlished. Across the entire plot crown nd trunk mesurements were recorded for ll trees over 9 ft tll. Mesurements included live crown height, tree height, crown dimeter, nd sl dimeter. To ensure the usefulness of the model we selected cnopy re s the predictor of iomss ecuse tree cnopy re is esily otined in the field nd cn e estimted using eril photogrphy. Crown re ws clculted using the following eqution: Cnopy re = π[(crown dimeter 1 + crown dimeter 2 /4)]² A su-smple of the trees mesured ws selected for destructive smpling t ech of the three sites (n = 99). Trees were felled, ll min rnches (those originting from the min trunk) were removed from the min stem, nd sectioned into mngele pieces (25 to 5 ls). All portions of the tree were seprted into four size clsses sed on stndrd fuel clsses: 1-hr (<.25 in), 1-hr ( in), 1-hr ( in) nd 1-hr (> 3. in). Smples from ech size clss were plced seprtely into trp nd weighed using lod scle. Su-smples were collected for ech size clss of ech tree t ech site. These susmples were oven dried t 14 F to determine field moisture content. The moisture content ws determined y weighing ech smple dily or weekly until constnt weight ws reched. Using the moisture content of the su-smple for ech size clss the field wet weights were converted to dry weights. RESULTS nd DISCUSSION A totl of 99 western juniper trees were destructively smpled cross ll three sites. Western juniper cnopy cover rnged from 3% to 63% with the lowest cover eing found t the Fort Rock site nd the highest cover t the Lkeview site. We found tree cnopy re ws relile predictor of totl tree iomss nd iomss of ll four fuel clsses (Tle 1). Totl iomss for single juniper rnged from 26 to 1,474 ls cross the three sites. For every squre foot of cnopy cover western juniper gins 2.25 ls of iomss. Figure 2 predicts western juniper iomss (ls/c) s percent cnopy cover. At the lndscpe or stnd scle, totl juniper iomss increses y 9,81 ls for every cre of cover (Tle 2). Of the four fuel clsses, the mjority of iomss ws in the 1-hour fuels clss, which ws composed mostly of tree folige (Fig. 3). 95

102 Tle 1. The reltionships etween cnopy cover nd the ove ground iomss of the four fuel clsses nd the totl iomss of western juniper. Dry weight is expressed in ls (y). Juniper cnopy re is expressed in squre feet (x). Figure 2. The reltionship etween percent cover nd iomss of western juniper cross the three study loctions (n=99 trees). 96

103 Tle 2. The reltionships etween cnopy cover nd the ove ground iomss of the four fuel clsses nd the totl iomss of western juniper t lndscpe scle. Dry weight is expressed in ls (y). Juniper cnopy re isexpressed in cres (x). Figure 3. The verge proportion of the different fuel clsses per individul western juniper. REFERENCES Birdsey, R.A., nd H.T. Schreuder An overview of forest inventory nd nlysis estimtion procedures in the estern United Sttes - with n emphsis on the components of chnge. USDA Forest Service Generl Technicl Report INT-GTR-129. Brown, J.K., R.F. Oerheu, nd C.M. Johnston Hndook for inventorying surfce fuels nd iomss in the interior west. USDA Forest Service Generl Technicl Report. INT