Thinning and Prescribed Fire and Projected Trends in Wood Product Potential, Financial Return, and Fire Hazard in Montana

Transcription

1 United Sttes Deprtment of Agriculture Forest Service Pcific Northwest Reserch Sttion Generl Technicl Report PNW-GTR-606 April 2004 Thinning nd Prescribed Fire nd Projected Trends in Wood Product Potentil, Finncil Return, nd Fire Hzrd in Montn R. Jmes Brbour, Roger D. Fight, Glenn A. Christensen, Guy L. Pinjuv, nd Ro V. Ngubdi

2 Authors R. Jmes Brbour is reserch forest products technologist, Roger D. Fight is reserch forester, Glenn A. Christensen is reserch forester, nd Guy L. Pinjuv nd Ro V. Ngubdi were foresters, U.S. Deprtment of Agriculture, Forest Service, Pcific Northwest Reserch Sttion, Forestry Sciences Lbortory, P.O. Box 3890, Portlnd, OR Pinjuv is currently doctorl cndidte, University of Cnterbury, Privte Bg 4800, Christchurch 8020, New Zelnd; Ngubdi is currently post-doctorl fellow, School of Forestry nd Wildlife Sciences, Auburn University, Auburn, AL

3 Abstrct Brbour, R. Jmes; Fight, Roger D.; Christensen, Glenn A.; Pinjuv, Guy L.; nd Ngubdi, Ro V Thinning nd prescribed fire nd projected trends in wood product potentil, finncil return, nd fire hzrd in Montn. Gen. Tech. Rep. PNW-GTR-606. Portlnd, OR: U.S. Deprtment of Agriculture, Forest Service, Pcific Northwest Reserch Sttion. 78 p. This work ws undertken under joint fire science project Assessing the need, costs, nd potentil benefits of prescribed fire nd mechnicl tretments to reduce fire hzrd. This pper compres the future mix of timber products under two tretment scenrios for the stte of Montn. We developed nd demonstrted n nlyticl method tht uses redily vilble tools to evlute pre- nd posttretment stnd conditions; size, species, nd volume of merchntble wood removed during thinnings; size nd volume of submerchntble wood cut during tretments; nd finncil returns of prescriptions tht re pplied repetedly over 90-yer period. Keywords: Wood products, thinning, fire hzrd, finncil return, Montn.

4 Executive Summry Findings This work ws initited under Joint Fire Science Progrm-funded project Assessing the needs, costs, nd potentil benefits of prescribed fire nd mechnicl tretments to reduce fire hzrd. We developed nd demonstrted n nlyticl method tht uses redily vilble tools to evlute pretretment nd posttretment stnd conditions; size, species, nd volume of merchntble wood removed during thinnings; size nd volume of submerchntble wood cut during tretments; nd finncil returns of prescriptions tht re pplied repetedly over 90 yers. In this pper we compre the potentil mix of timber products recovered under two tretment scenrios pplied in Montn. The tretment scenrios simulted here were not intended s solutions to the fuel hzrd problem per se. They re, however, representtive of pproches tht re currently being pplied on the ground, nd our intention ws to illustrte (1) the use of existing tools to evlute the effectiveness nd cost of implementing these types of tretments nd (2) the likely results of repetedly pplying these tretments over long timefrmes. There re importnt policy issues ssocited with both prts of the nlysis. Our nlysis suggests tht only reltively smll proportion of existing stnds could be treted without subsidy if either of the prescriptions modeled here is used. Even so, lmost 1,000,000 cres could be treted without subsidy. Fire hzrd is initilly reduced by these tretments. The effects of subsequent tretments rnge from brely mintining the initil improvement to continuous improvement over 10-decde period. Projections of repeted pplictions of these tretments suggest tht they lso could hve unintended consequences by creting conditions conducive to brk beetle (Dendroctonus spp.) outbreks or by reducing stnd densities below cceptble levels. Neither option studied provided for regenertion of stnds, so geclss distribution would eventully become problem in stnds mnged under either prescription. Our min conclusions, therefore, re tht (1) it is importnt to consider the long-term consequences of fuels tretments nd (2) existing tools cn provide useful informtion bout the short- nd long-term effects of mny proposed tretments. A vriety of silviculturl tretments cn be modeled by using these methods. One of the tretments we chose to illustrte the methods ws to thin from below to 9 in dimeter t brest height (d.b.h.) with minimum residul bsl re (BA) nd follow with prescribed burn, then every 30 yers to reevlute for thinning nd to burn whether rethinned or not (TB9). The key findings of tht scenrio follow. The initil effect of this prescription on fire hzrd ws modest. Repet entries did little more thn mintin the initil gins. There ws substntil long-term downwrd trend in the projected bsl re mortlity expected during prescribed burn tretments. Bsl re built up over time, perhps to levels tht would put the stnds t risk of insect outbreks. There ws no merchntble volume hrvested under this prescription fter the first thinning. No cses were found where the hrvested mteril would cover the cost of conducting the thinning either currently or in future entries given existing mrket conditions. (If volumes removed from skid trils or cble corridors were included in these clcultions, the results might hve been different.)

5 If the TB9 prescription were widely implemented nd if policy clled for utiliztion of the removed volume, investments in new processing cpcity would be necessry becuse this prescription yields only submerchntble trees fter the first entry. The other tretment we chose ws to thin from below up to 50 percent of stnding bsl re with minimum residul bsl re nd follow with prescribed burn, then every 30 yers reevlute for thinning nd burn whether rethinned or not (50BA). The key findings of tht scenrio follow. The initil effect of this prescription on fire hzrd ws modest, but there ws continued improvement with successive entries. There ws substntil long-term downwrd trend in the projected bsl re mortlity expected during prescribed burn tretments. Bsl re stbilized ner the minimum residul bsl re required under the prescription. The merchntble volume hrvested ws lower in future entries thn in the initil entry, but the d.b.h. of hrvested trees incresed to greter thn 16 in over the simultion period. The prescription mde no provision for regenerting the stnd, so repeted entries often lowered the number of trees per cre to well below full stocking levels. In prctice, mngers would lmost certinly lter prescriptions to regenerte stnds before this hppened. Typiclly, less thn 20 percent of the high-hzrd plots hd net finncil returns of more thn $100 per cre, but this mounted to more thn 790,000 cres of Dougls-fir nd lmost 180,000 cres of ponderos pine where this tretment could potentilly be implemented without subsidy. Most cses showed positive net return from thinnings by the end of the simultion period. The results suggest tht both of the simulted prescriptions reduced fire hzrd over the long term, but they were not eqully effective. Over the course of severl entries, the bsl-re-limited prescription creted stnds tht were open with few scttered lrge trees, wheres the dimeter-limited prescription creted dense stnds with mny midsize trees. The dimeter-limited prescription sometimes resulted in combintions of bsl re, tree size, nd stnd ge tht rise concerns over insect outbreks, specificlly Dougls-fir beetles (Dendroctonus pseudotsug Hopkins), western pine beetles (D. brevicomis Le Conte), nd mountin pine beetles (D. ponderose Hopkins). In generl, however, it ws possible to use these tretments to develop wide rnge of density nd tree size combintions over the simultion period. Even with the simple prescriptions modeled here, it would be possible to select stnds with different initil conditions nd ges nd pply the prescriptions t different times to develop diverse set of conditions on lndscpe. We did not explore such sptil or temporl rrngements of tretments, but this undoubtedly would be importnt when developing mngement plns tht consider the interctions of fuel reduction tretments with multiple resource vlues nd episodic disturbnces on lrge lndscpes.

6 In terms of wood utiliztion, the nlysis showed tht the dimeter-limited prescriptions produced only smll volumes of smll trees from the first entry nd miniml volumes in subsequent entries. These prescriptions lmost universlly hd negtive net returns, even without considering the costs of regulr cycle of prescribed fire, so substntil subsidy would be required to implement them. If these prescriptions were widely implemented nd if industril cpcity were developed to use the wood removed under them, it would be importnt to size processing plnts nd develop tretment schedules to ensure sustinble supply of rw mteril. The bsl-re-limited tretment produced more volume thn the dimeter-limited prescription nd sometimes showed positive net return. This prescription produced trees nd logs in vriety of sizes. Although the verge dimeter of cut trees incresed with successive entries, the totl volume per thinning generlly declined over time.

7 Contents 1 Introduction 2 Geogrphic nd Forest Type Detil 2 Methods nd Assumptions 4 Fire Hzrd Reduction Tretments 4 Forest Vegettion Simultor Vrints 4 Prescriptions 5 Effectiveness of Hzrd Reduction Tretments 5 Finncil Anlysis 6 Results nd Discussion 6 Dougls-Fir 13 Ponderos Pine 20 Conclusion 22 Metric Equivlents 22 Literture Cited 24 Acronym Glossry 24 Appendix 1 Cost nd Log Price Assumptions 26 Appendix 2 Acrege nd Number of Inventory Plots 28 Appendix 3 Averge Initil Stnd Chrcteristics 32 Appendix 4 Averge Residul Stnd Chrcteristics 41 Appendix 5 Averge Volume of Utilized Trees 50 Appendix 6 Averge Volume of Unutilized Trees 59 Appendix 7 Averge Smll-End Dimeter of Utilized Logs 62 Appendix 8 Averge Percentge of Volume, by Species, of Utilized Trees 71 Appendix 9 Averge Proportion of Stnds by Net Vlue Ctegory

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9 Introduction This study ws undertken with funding from the Joint Fire Science Progrm (JFSP) to develop protocols for use in determining the mgnitude of hzrd reduction tretment needs, tretment cost, nd ssocited benefits t stte level. The objectives of the study include (1) quntifying existing stnd conditions for mjor forest types in terms of density, structure, nd species composition, nd prioritizing by need for hzrd reduction tretment, (2) developing nd compring lterntive cutting nd prescribed burning prescriptions for reducing high-hzrd conditions in mjor forest types, (3) determining potentil revenue from timber products generted from the hzrd reduction hrvest tretments, (4) compring the future mix of timber products under lterntive tretment scenrios, nd (5) describing the potentil for nlyzing noncommodity resources under tretment nd no-tretment scenrios. This report demonstrtes the protocols developed under JFSP funding to nlyze nd illustrte trends in the longterm effects of repeted hzrd reduction entries in terms of the stocking, size, nd species mix of residul stnds nd the size nd species mix of trees nd logs tht might be removed nd used for wood products. Montn ws selected s n exmple becuse recent inventories were vilble. Montn s forest products industry is well estblished with the technologicl cpbility to process the numerous smll-dimeter logs expected from fuel hzrd reduction tretments. A similr nlysis ws conducted for New Mexico where the existing industry is smll nd not gered towrd using this type of mteril (see Fight et l. 2004). If widely dopted, the types of tretments proposed s mens of reducing forest fire hzrds could hve implictions for future forest conditions s profound s pst mngement prctices, principlly hrvesting nd fire exclusion tht led to the existing conditions. Chnges of tht mgnitude hve the potentil to ffect mny forest vlues such s fisheries, wildlife, timber, nontimber forest resources, environmentl services, nd menities. Some of these chnges will likely be considered positive nd some will likely be considered negtive. How they re viewed depends on the resource in question nd the reltive importnce given to different resource vlues. It is neither our plce nor our intent to sy which chnges re more importnt or whether they re desirble or undesirble. Our intent is to provide set of protocols tht use existing tools 1 nd dt 2 tht re vilble to nlysts employed by federl, stte, nd privte lnd mngement orgniztions. The interprettions we provide in this report re intended s neutrl exmples illustrting these protocols. Our protocols cn be used to conduct nlyses nd disply informtion bout fire hzrd, stnd conditions, nd removed mterils. We nticipte tht this informtion will be useful to decisionmkers who formulte fire mngement policy nd devise implementtion strtegies. 1 For exmple, Forest Vegettion Simultor (FVS), Fire nd Fuels Extension (FFE), Finncil Evlution of Ecosystem Mngement Activities (FEEMA), Microsoft Access (the use of trde or firm nmes in this publiction is for reder informtion nd does not imply endorsement by the U.S. Deprtment of Agriculture of ny product or service), etc. (see Methods nd Assumptions section). 2 We used forest inventory nd nlysis (FIA) plot-level dt, but mny types of stnd-level dt re dequte for these protocols. 1

10 The types of tretments proposed to reduce fire hzrd could lso hve importnt implictions for the volume nd chrcteristics of timber vilble for the production of forest products. Significnt shifts in the species or size composition, for exmple, could influence the economic vibility of the industry nd ffect the economic helth of the people nd communities in which timber processing occurs. This report is intended to supply informtion to brod rnge of decisionmkers concerned with forest fire hzrd including federl, stte, nd privte forest lnd mngers, plnners, nd others with n interest in the mngement of forests in the Western United Sttes. Geogrphic nd Forest Type Detil Methods nd Assumptions Montn ws divided into western nd estern regions for nlysis nd reporting. The division generlly follows the Continentl Divide. Within ech geogrphic re, forests were further divided into 11 forest types: Dougls-fir (Pseudotsug menziesii (Mirb.) Frnco), lodgepole pine (Pinus contort Dougl. ex Loud.), ponderos pine (Pinus ponderos Dougl. ex Lws.), moist low-elevtion mixed conifers, dry low-elevtion mixed conifers, upper-elevtion mixed conifers, western lrch (Lrix occidentlis Nutt.), spruce/fir (Pice spp./abies spp.), sublpine fir (Abies lsiocrp (Hook.) Nutt.), quking spen (Populus tremuloides Michx.), nd cottonwood (Populus spp.). We performed our nlyses on the Dougls-fir nd ponderos pine forest types becuse they were identified by the Montn technicl contct tem 3 (TCT) s being of high concern nd hving high potentil for hzrd reduction tretments. These forest types hve reltively short fire-return intervls nd re likely cndidtes for hzrd reduction tretments. They were lso extensive enough to supply sufficient forest inventory nd nlysis (FIA) dt with which to provide meningful illustrtion of our protocols. We report results by two ownership ctegories: ntionl forest lnd nd other lnd. These ctegories were chosen to mke the most efficient use of the vilble FIA dt. With dditionl stnd exm dt it would be possible to further refine ownership clsses. In this report ech combintion of region, owner group, forest type, slope ctegory, nd hzrd ctegory is referred to s cse nd ech ppliction of tretment ( thinning or prescribed fire) within ech cse is referred to s n entry. Reporting within the two ownership clsses ws further broken down into current forest fire hzrd condition nd slope. The mximum number of reporting ctegories (cses) for the Montn study ws 32 (2 regions by 2 owner groups by 2 forest types by 2 slope ctegories by 2 hzrd ctegories). The objective of this nlysis ws to show the results of two stnd tretment options intended to reduce fire hzrd both now nd in the future. Evlutions include (1) residul stnd structure, (2) volume, size, nd chrcteristics of merchntble trees cut through time, (3) the volume nd size of submerchntble (biomss) trees cut through time, nd (4) the finncil fesibility of tretments. A detiled description of our modeling techniques is given by Christensen et l. (2002) We used existing modeling tools nd inventory dt linked in wy tht llowed comprehensive nlysis over rnge of tretment options. Primry tools included the Forest Vegettion Simultor (FVS) growth nd yield model (Crookston 1990, Stge 3 A group of experts were ssembled to comment on the design of nd outcomes from this nlysis. They re Donld Artley, Montn Deprtment of Nturl Resources nd Conservtion; Dnny Cstillo, USDA Forest Service Northern Region; Dennis Dupuis, Slish nd Kooteni Tribl Forestry; Bruce Reid, USDI Bureu of Lnd Mngement; nd Gordy Snders, Montn Tree Frmers nd Pyrmid Lumber. 2

11 1973), the Fire nd Fuels Extension (FFE) model s prt of FVS (Beukem et l. 1997, Scott nd Reinhrdt 2001), nd the Finncil Evlution of Ecosystem Mngement Activities (FEEMA) model (Fight nd Chmelik 1998). Dt were stored in Microsoft Access dtbse, nd stndrd set of reports ws developed within the dtbse. Use of these tools mkes the nlysis portble to nywhere in the Western United Sttes where n FVS vrint with n FFE extension nd FEEMA vrint re vilble. The tools re fmilir to, or cn be redily lerned by, forest plnning nd nlysis stff within federl gencies nd most stte or privte orgniztions. Where they exist, other growth models, fire models, nd finncil models could be substituted for the ones we used. Mesurements of current forest vegettion re from dt collected by the Forest Service FIA progrm. Our methods re generl, however, nd dequte dt cn be obtined from wide rnge of stnd exm or other stnd-level dt tht re suitble for use s input dt to FVS. An importnt cvet here is tht stnd-level dt should be collected in such wy tht they comprise sttisticlly representtive smple of the vegettion popultion on the trget lndscpe. We exmined 678 cndidte FIA plots with smpling weight of pproximtely 6,000 cres ech. When more thn 50 plots were vilble for given cse, 4 smple of 50 plots ws rndomly selected to represent ll the re in tht cse. When fewer thn 50 plots were vilble for given cse, ll of the plots were used in the nlysis. Cses with fewer thn 10 plots were not included in the nlysis becuse there were insufficient dt to dequtely represent potentil vrition. Alterntively, it is possible to nlyze ll plots regrdless of smple size nd exmine results for individul plots rther thn verge results. We felt tht this method would be tedious nd not llow us to provide compct illustrtion of our methods. Individul nlysts might, however, be interested in identifying plot conditions where the probbility of some desired outcome, such s finncilly vible ctivities, is high. In tht cse, nlysis of individul plots might be desirble. Fire hzrd rting is bsed on estimtes of the crowning index for ech decde provided by the FFE of FVS. Crowning index is the windspeed necessry to sustin crown fire. It is clculted from the crown bulk density for the stnd. The lower the crowning index, the higher the probbility tht crown fire will be sustined (Scott nd Reinhrdt 2001). Crowning index vlues reported re fter thinning (if clled for) nd prescribed fire tretment. Forest inventory nd nlysis dt were converted into FVS input files, nd silviculturl tretment regime ws simulted. The silviculturl regimes simulted in this nlysis were intentionlly kept simple to provide n uncomplicted illustrtion of the protocols nd to provide benchmrk results tht could be used to refine tretment options. In other prts of this study nother more complex prescription ws used, but it ws not used in our nlysis becuse we were unble to model it in FVS. 5 4 Ech cse is the combintion of ownership, forest type, fire hzrd, nd slope. 5 Fiedler, C.E.; Keegn, C.E., III; Woodll, C.W. [et l.] A strtegic ssessment of fire hzrd in Montn; A strtegic ssessment of fire hzrd in New Mexico. Reports submitted to the Joint Fire Science Progrm Bord, 3833 S. Development Ave., Boise, ID

12 For ech hrvest mde in FVS, list of cut trees ws recorded nd then imported into the FEEMA model. The FEEMA model determined merchntbility of ech tree, bsed on minimum smll-end dimeter (SED) of 5.0 in inside the brk nd minimum log length of 8 ft for upper logs nd 16 ft for butt logs. The FEEMA model tllied individul logs nd produced n output file summrizing volume by species, tree dimeter t brest height (d.b.h.), nd log SED. These results were compiled in dtbse. Results from the simultions were clculted s the verge of the FIA plots selected for ech cse (50 or fewer s described bove) weighted by the pproprite plot expnsion fctor (the number of cres represented by plot). Whole-tree stem volumes of biomss (submerchntble) trees from 1 to 7 in d.b.h. were estimted by using FVS. We did not clculte totl biomss (totl stem, limbs, nd folige) volume or weight for the biomss trees. Fire Hzrd Reduction Tretments Forest Vegettion Simultor Vrints Prescriptions Silviculturl prescriptions were developed in consulttion with the TCT. The objective ws to cover rnge of tretment options. In generl, tretment cn be thinning, thinning followed by burning (prescribed fire), or mintennce burn (prescribed fire) without thinning. We used thinning tretments tht included thinnings from below to different dimeter nd bsl re trgets, followed by prescribed burn. Thinning ws simulted with FVS. Prescribed burning ws simulted by using the FFE model. The crowning index from the FFE model ws used s surrogte for fire hzrd. We segregted ll plots into high, medium, nd low fire hzrd bsed on crowning indices, which re expressed s windspeed of <25 mph (high hzrd), 25 to <50 mph (moderte hzrd), nd 50+ mph (low hzrd). For the ponderos pine forest type we grouped the plots with high nd medium fire hzrd, nd in the Dougls-fir forest type we grouped the plots with medium nd low fire hzrd. For reporting purposes, output tbles re lbeled s high or low fire hzrd with the grouping indicted t the beginning of the results section for ech forest type. This designtion indictes the reltive importnce of treting stnds in the indicted crowning index clsses for tht forest type. Tretments in plots designted s low were deferred for one tretment simultion cycle (30 yers). Three FVS vrints were used for this nlysis. The estern Montn vrint ws used for ll of estern Montn. In western Montn, the northern Idho vrint ws used except for the Kooteni Ntionl Forest nd the Tlly Lke Rnger District of the Flthed Ntionl Forest where the Kooteni vrint ws used. Two generlized prescriptions were pplied to both forest types. The first ws thinfrom-below to 9 in d.b.h. It is referred to s TB9 in the text. The second is thin-frombelow to up to 50 percent of stnding bsl re. It is referred to s 50BA in the text. Detils of the tretment for ech forest type nd geogrphic loctions follow. Dougls-fir The thinning reentry intervl is 30 yers with prescribed burning immeditely following ech entry (thinning nd burning included in the sme FVS simultion cycle). The TB9 prescription required minimum residul bsl re of 45 ft 2 /c in western Montn nd 40 ft 2 /c in estern Montn. The 50BA prescription required minimum residul bsl re of 80 ft 2 /c in western Montn nd 70 ft 2 /c in estern Montn. Stnds tht did not hve sufficient bsl re to qulify for thinning were burned nd were reconsidered for thinning t the next thinning cycle (30 yers). 4

13 Ponderos pine The thinning reentry intervl is 30 yers with prescribed burning immeditely following ech entry (thinning nd burning included in the sme FVS simultion cycle). The TB9 prescription required minimum residul bsl re of 40 ft 2 /c in western Montn nd 35 ft 2 /c in estern Montn. The 50BA prescription required minimum residul bsl re of 50 ft 2 /c in western Montn nd 40 ft 2 /c in estern Montn. Stnds tht did not hve sufficient bsl re to qulify for thinning were burned nd were reconsidered for thinning t the next thinning cycle (30 yers). Effectiveness of Hzrd Reduction Tretments Finncil Anlysis Liner regression nlysis ws used to identify trends in the long-term effectiveness of tretments in lowering fire hzrd. The regression tested for time trend nd tretment effect in the predicted crowning index. The dependent vrible in these regressions ws the verge predicted crowning index for the high-hzrd plots for given forest type nd tretment. The independent vribles were decdes numbered from 1 to 10, dummy vrible for decde of tretment, nd dummy vrible for the decde following tretment. Dummy vribles hve vlue of 1 for dt points tht hve the ttribute nd zero otherwise. The model form ws Y = + b(decde) + c(decde of tretment dummy) + d(decde following tretment dummy). Any of the three vribles tht were not sttisticlly significnt t the 5-percent level were deleted from the model, nd the model ws rerun. Results from this nlysis helped to illustrte whether there ws improvement in crowning index immeditely fter entries or during the decde following entries, how crowning index chnged between entries, nd whether there ws long-term trend of improvement in crowning index. A similr nlysis ws used to identify trends in the verge bsl re mortlity expected from the prescribed burns. The dependent vrible in these regressions ws the verge predicted bsl re mortlity (percentge) for prescribed burn for the high-hzrd plots for given forest type nd tretment. The FEEMA model ws used to rte the potentil net revenue from the thinnings. The nlysis ws done for single set of economic ssumptions tht represent mixed mrket conditions. The mrket conditions used represent mrket for lumber nd mrket for chip logs down to 5 in SED. Although the pricing ws done on log bsis rther thn the tree bsis used in nother prt of the study, the prices were mde s comprble s possible (see footnote 5). The finncil returns should be regrded s optimistic becuse of the ssumed mrket for chip logs, but useful in identifying the reltive finncil fesibility of different cses nd chnges in fesibility of future versus current tretments. Costs included cutting smll trees tht re cut nd treted in plce nd cutting trees tht re used for products. Costs of other hrvest-relted ctivities such s rod building or repir nd environmentl remedition, which cn vry widely, were not included, nor were revenues ssocited with timber removed from skid trils or cble corridors. Ground-bsed equipment ws ssigned lower cost thn cble yrding systems. Stump-to-truck costs were bsed on Hrtsough et l. (2001). Ground-bsed equipment ws ssumed on slopes of less thn 35 percent. Huling costs were $28 per 100 ft 3 for ll species nd res. See ppendix 1 (tbles 1 through 3) for full description of economic ssumptions. 5

14 Results nd Discussion Dougls-Fir The totl re nd number of FIA inventory plots included in this nlysis for the Dougls-fir forest type re shown in ppendix 2 (tble 4). Dougls-fir plots were segregted by high crowning index (<25 mph windspeed) nd low/moderte crowning index (25+ mph windspeed) for the nlysis presented here. For brevity, these two groups re referred to s high fire hzrd nd low fire hzrd in ll of the tbles for this species. Tretment effect on fire hzrd Regression nlysis indicted both time trend (positive coefficient on decde) nd cyclicl tretment effect ( positive coefficient on the decde following tretment) on verge crowning index for the 50BA prescription in the Dougls-fir high-hzrd stnds. This mens tht ech subsequent tretment brought the crowning index higher ( lower hzrd) thn the previous tretment. The results from the Dougls-fir high-hzrd stnds with TB9 tretment hd cyclicl tretment effect ( positive coefficient on the decde following tretment) nd smll time trend. There ws improvement with ech entry, but fter the initil increse, the crowning index declined to level only slightly bove the previous entry by the time of the next entry. These comprisons re clerly seen in the plot of the predicted verge vlues for fire hzrd index shown in figure 1. Recll tht the crowning index for ll high-hzrd plots ws initilly less thn 25, so the first point in the figure includes the improvement ssocited with the initil tretment. Figure 2 shows the nlogous comprison for the predicted verge bsl re mortlity resulting from prescribed burns. In spite of the fct tht the effect on crowning index is quite different between the tretments, the effect on potentil bsl re mortlity is strikingly similr. This mens tht even though the bility to crry crown fire is different, the bility of the trees to withstnd low-intensity fires, such s prescribed fire, is similr. By the 10 th decde of the simultion, expected bsl re mortlity drops to round 5 percent for both prescriptions. Initil stnd summry The initil stnd conditions for high- nd low-fire-hzrd cses differ systemticlly when pired by geogrphic region, owner, nd slope. The low-hzrd cses consistently hve lower bsl re, fewer trees per cre, nd lrger qudrtic men dimeters (QMD) (pp. 3, tbles 6 through 9). A typicl comprison is shown for western Montn in figure 3. Residul stnd summry The results presented in figure 4 illustrte how stnd conditions would chnge over time for Dougls-fir plots. Although the results shown in the figure re for Forest Service lnd in western Montn, they re similr to those for other ownerships nd geogrphic regions in Montn (pp. 4, tbles 14 through 17). When the two prescriptions re pplied repetedly over the course of century, our nlysis suggests tht the 50BA prescription will result in less-crowded stnd conditions with fewer but lrger trees thn the TB9 prescription. The min difference between the tretment projections is tht the dimeter-limited prescription (TB9) resulted in n ccumultion of bsl re over time, wheres the bsl-re-controlled prescription (50BA) reduced bsl re to the minimum vlue, 80 ft 2 /c in this cse, nd kept it there throughout the simultion. Under the dimeter-limited prescription, bsl re nd QMD incresed over time while trees per cre declined. This hppened becuse the prescription generlly removed ll of the trees under 9 in before the minimum bsl re ws reched. Bsl re incresed becuse the trees over 9 in d.b.h. were never removed, nd s they grew, bsl re continued to ccumulte. Trees per cre declined becuse few, if ny, trees under 9 in 6

15 Figure 1 Predicted verge crowning index over time for high-fire-hzrd Dougls-fir plots in Montn by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. Figure 2 Predicted verge bsl re mortlity over time for high-fire-hzrd Dougls-fir plots in Montn by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. 7

16 Figure 3 Initil stnd conditions for Dougls-fir plots on steep slopes in western Montn: bsl re, number of trees per cre, nd qudrtic men dimeter, reported by gentle slope low or high fire hzrd (GSLH or GSHH) nd steep slope low or high fire hzrd (SSLH or SSHH). survived to become lrge trees, but some of those lrger thn 9 in died in ech growing cycle (10 yers). With no understory trees to replce them, the number of trees per cre declined over time. The ccumultion of bsl re projected under the TB9 prescription is n issue tht forest mngers or plnners might wnt to consider more closely. Our nlysis suggests tht this prescription will generlly be sufficient to keep treted stnds in the moderte fire hzrd clss nd tht mortlity ssocited with prescribed burns, nd presumbly other low-intensity fires, will decline over time under both prescriptions. Stnds mnged under these prescriptions for long time, however, will hve very different structures. Both of these stnd structures might be regrded s desirble components of lndscpe t some level. The 50BA prescription cretes open stnds with scttered lrge trees. The TB9 prescription cretes densely stocked stnds with trees more uniform in size. In some cses, the resulting conditions rech point where the stnds re high hzrd for Dougls-fir brk beetle (Dendroctonus pseudotsug Hopkins) outbreks. 6 Neither prescription llows for regenertion of n understory nd recruitment of smller trees into the overstory, so both will eventully led to single-story stnds. 6 Gibson, K Personl communiction. Entomologist, U.S. Deprtment of Agriculture, Forest Service Forest Helth Protection, P.O. Box 7669, Missoul MT

17 Figure 4 Residul conditions projected for Dougls-fir plots on steep slopes with high fire hzrd on ntionl forests in western Montn (verge vlues for thinned plots only): bsl re, number of trees per cre, nd qudrtic men dimeter, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. Merchntble volume by dimeter t brest height clss Dt for verge removed volume of trees 7 in d.b.h. nd lrger re reported in ppendix 5 (tbles 22 through 25). As rule of thumb, sle dministrtors experienced with smll-dimeter timber sles typiclly look for t lest 600 ft 3 of removed volume per cre. 7 None of the cses reported for the TB9 prescription yield tht much volume, but 12 of the 16 cses under the 50BA prescription did yield t lest 600 ft 3 /c in the first entry. In some cses, the merchntble volume in the first entry ws more thn 1,000 ft 3 /c. An exmple of the chnge in hrvest volume for one cse by entry is shown in figure 5. The TB9 prescription did not result in ny merchntble volume fter the first entry, nd this ws lso true for ll other cses using this prescription. The gretest volume ws removed from the 50BA prescription during the first entry, nd the volume removed in the second entry ws less thn the first in ll but one cse. In some cses, the volume remined firly constnt over time from the 50BA prescription, but in others it continued to decline s it does in figure 5. 7 Wynsm, B Personl communiction. Timber sle dministrtor, U.S. Deprtment of Agriculture, Forest Service, Idho Pnhndle Ntionl Forest, Bonners Ferry Rnger District, Bonners Ferry, ID

18 Figure 5 Averge merchntble volume projected to be removed from Dougls-fir plots on ntionl forests in western Montn on steep slopes with high fire hzrd, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. The chrcteristics of the volume removed under the 50BA prescription lso chnge considerbly over time (fig. 6). At the beginning of the simultion period (2000), most of the volume removed ws in the 7- to 10-in nd 10- to 13-in d.b.h. clsses. By the second entry (2030), lmost no volume ws in these clsses, nd most of the volume cme from trees greter thn 13 in d.b.h. Volume removed during the third nd fourth entries cme lmost exclusively from trees greter thn 16 in d.b.h. Stem biomss volume of trees 1- to 7-in dimeter t brest height Totl stem volumes of cut trees less thn 7 in d.b.h. re illustrted in figure 7. Under both prescriptions the initil entry yields by fr the lrgest volume of trees in the 1- to 7-in d.b.h. clss. After the initil entry, the volume of smll trees tht were cut sometimes fluctuted with either prescription, but it lwys remined well below the initil volume. Detiled results for ll cses re found in ppendix 6 (tbles 30 through 33). There currently is not relible pulp mrket in Montn nd no biomss mrket. Assuming moisture content of 50 percent nd specific grvity of 0.40, these volumes convert to 6 to 10 green tons per cre. This estimte does not include limbs nd folige, so the totl biomss could be considerbly higher. These trees re either n opportunity or disposl problem depending on whether mrkets re developed for them. Anlyses like this one might prove useful when considering siting biomss-processing fcilities, but scheduling of tretments lso is n importnt issue becuse most of the volume occurs in the initil entry. Over time the supply of smll trees would be expected to decline following brod ppliction of either prescription. Averge smll-end dimeter of removed logs The TB9 prescription lwys produces logs tht re only slightly lrger thn 5 in with smll-end dimeters rnging from 5.0 to 5.7 in (pp. 7, tble 38). This hppens becuse the lrgest merchntble tree removed under this prescription is 9 in d.b.h., nd such trees do not yield logs much lrger thn 5 in SED. With current technology, lrge volumes of logs in this size rnge 10

19 Figure 6 Averge merchntble volume projected to be removed from Dougls-fir plots on ntionl forests in western Montn on steep slopes with high fire hzrd, by tree dimeter t brest height. Figure 7 Projected nonmerchntble volume in trees 1- to 7-inch dimeter t brest height cut from Dougls-fir plots on ntionl forests in western Montn on steep slopes with high fire hzrd, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. would crete problem for conventionl solid wood processors becuse of the inefficiencies of mnufcturing either lumber (Brbour 1999) or veneer (Christensen nd Brbour 1999). Progress hs been mde recently in identifying lterntive uses for such smll-dimeter logs, e.g., structurl round wood (LeVn-Green nd Livingston 2001, Wolfe nd Hernndez 1999), but mrkets re poorly developed. 11

20 Figure 8 Volume-weighted verge log smll-end dimeters for wood projected to be removed from Dougls-fir plots on ntionl forests in western Montn on steep slopes with high fire hzrd, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. Log SED increses over time for the 50BA prescription s expected in light of the comprison of tree sizes (fig. 8). Most cses rech verge SEDs of 10 in or more in the third entry, nd modern rndom-length dimension swmills often process logs tht verge less thn 10 in, 8 so this mix of logs is well suited for mny existing mills. Although the size of the logs increses over time for the 50BA prescription, the verge merchntble volume removed decreses by more thn one-third over the sme period (fig. 5). The ctul reduction my be more thn shown here becuse sometimes stnds tht were thinned in the first cycle do not qulify to be thinned in subsequent cycle nd re excluded from the verges shown in this figure. This mens tht lthough the qulity of the rw mteril might increse over time, the quntity could decline depending on the scheduling of tretments within fixed re. Percentge of volume removed, by species In ll cses most of the volume removed under both prescriptions is Dougls-fir. Representtive results re presented in figure 9. There ws little difference in the species composition of the hrvested mteril under the two prescriptions. White wood (true firs, spruce, lodgepole pine, nd other minor conifer species) proportion of the hrvested volume removed is slightly higher during the first entry thn lter, but over time there is no rel species shift. These results suggest tht if species-dependent processing options were estblished in n re where lrge-scle fire hzrd reduction tretments in Dougls-fir stnds were tking plce, differences in tree size from the two prescriptions would likely be more importnt issue thn species mix. Detiled results for ll cses re found in ppendix 8 (tbles 40 through 43). 8 Armstrong, R Personl communiction. Vice President, USNR Corportion, 558 Robinson Rd., Woodlnd, WA

21 Figure 9 Percentge of sw log volume, by species projected for Dougls-fir plots on ntionl forests in western Montn on steep slopes with high fire hzrd. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. Finncil nlysis Results from the finncil nlysis suggest tht in mny cses the first entry will require subsidy of $100 or more per cre for either the TB9 or 50BA prescription. In fct, ll of the plots treted with the TB9 prescription required t lest $100 per cre subsidy. The sitution improved over time under the 50BA prescription (fig. 10). Except for the first entry, no merchntble volume ws removed under the TB9 prescription, so ctivities under tht prescription lwys hd negtive net returns. These estimtes include the costs of treting mteril tht is not economicl to use for products. They do not include the costs of prescribed fires, which occur on 30-yer cycle on high-hzrd stnds whether or not plots re thinned. They lso occur on 30-yer cycle on low-hzrd stnds, but do not strt until the beginning of the second cycle. The finncil results re summrized for ll cses in ppendix 9 (tbles 48 through 51). Ponderos Pine The totl re nd number of FIA inventory plots included in this nlysis for the ponderos pine forest type re shown in ppendix 2 (tble 5). Ponderos plots were segregted by high/moderte hzrd (<50 mph windspeed) nd low hzrd (50+ mph windspeed) for the nlysis presented here. For brevity, these two groups re referred to s high fire hzrd nd low fire hzrd in ll of the tbles for this species. Tretment effect on fire hzrd Regression nlysis indicted both time trend (positive coefficient on decde) nd cyclicl tretment effect (positive coefficients for the decde of tretment nd the decde following tretment) on verge crowning index for the 50BA prescription in the ponderos pine high-hzrd plots. This mens tht ech subsequent entry brought the crowning index higher ( lower hzrd) thn the previous entry. The results from the ponderos pine high-hzrd plots using the TB9 prescription showed no trend for improvement over time, nd there ws only smll effect in the decde following tretment. The effect is smll enough tht the 13

22 Figure 10 Net vlue per cre projected for the 50BA prescription from Dougls-fir plots on ntionl forests in western Montn on steep slopes with high fire hzrd. hzrd index hovers round 50 mph throughout the 10-decde period. These comprisons re clerly seen in plot of the predicted verge vlue for fire hzrd index in figure 11. Figure 12 shows n nlogous comprison for the predicted verge bsl re mortlity from prescribed burns. In spite of the fct tht the effects of the two prescriptions on crowning index re quite different, their effects on potentil bsl re mortlity re strikingly similr. This mens tht even though the likelihood tht trees will crry crown fire is different for ech prescription, the bility of the trees to withstnd prescribed fire is similr, with expected bsl re mortlity dropping to round 5 percent in both cses over the projection period. This result suggests tht by the 10 th decde of the simultion, both prescriptions crete stnd conditions where trees re reltively resilient to low-intensity fires. Initil stnd summry The initil stnd conditions for high- nd low-fire-hzrd cses differ systemticlly when pired by geogrphic region, owner, nd slope. The low-hzrd cses consistently hve lower bsl re, fewer trees per cre, nd lrger qudrtic men dimeters (pp. 3, tbles 10 through 13). Typicl comprisons re shown for both ntionl forest lnd nd other forest lnd in western Montn (fig. 13). Residul stnd summry The results presented in figure 14 illustrte how stnd conditions chnged over time for ponderos pine plots. Although the results shown in the figure re for Forest Service lnd in western Montn, they re similr to those for other ownerships nd geogrphic regions in Montn (pp. 4, tbles 18 through 21). Our nlysis suggests tht when repetedly pplied over the course of century, the 50BA prescription will result in less-crowded stnd conditions with fewer but lrger trees thn the TB9 prescription. 14

23 Figure 11 Predicted verge crowning index for high-fire-hzrd ponderos pine plots in Montn, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. Figure 12 Predicted verge bsl re mortlity for high-fire-hzrd ponderos pine plots in Montn, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. 15

24 Figure 13 Initil stnd conditions for ponderos pine plots in western Montn: bsl re, number of trees per cre, nd qudrtic men dimeter, reported by gentle slope low or high fire hzrd (GSLH or GSHH) nd steep slope low or high fire hzrd (SSLH or SSHH). As with Dougls-fir, the dimeter-limited prescription (TB9) resulted in n ccumultion of bsl re over time, wheres the bsl-re-controlled prescription (50BA) reduced bsl re to the minimum vlue for this forest type, 9 nd kept it there throughout the simultion. Bsl res in plots treted under the TB9 prescription rech n verge of 90 ft 2 /c in the second or third tretment cycle, nd fter century they were ll over 100 ft 2 /c. These plots re reching the combintions of ge nd bsl re where they would be considered t risk for ttck by mountin pine beetles (Dendroctonus ponderose Hopkins) nd western pine beetles (D. brevicomis Le Conte) (see footnote 6). If such regimes re followed on lrge proportion of the lndscpe, extensive insect outbreks could eventully become problem. Merchntble volume by tree dimeter t brest height clss Dt for verge removed merchntble volume of trees 7 in d.b.h. nd lrger re reported in ppendix 5 (tbles 26 through 29). As with Dougls-fir, cut volumes were not high. In 7 of the 13 cses where there were sufficient dt to conduct the nlysis, more thn 600 ft 3 /c ws removed under the 50BA prescription for t lest one entry. Five of those cses yielded more thn 600 ft 3 /c in more thn one entry. In contrst, hrvested volume never verged more thn 150 ft 3 /c under the TB9 prescription. 9 Bsl res of 50 ft 2 /c in western Montn nd 40 ft 2 /c in estern Montn. 16

25 Figure 14 Residul conditions projected for ponderos pine plots on steep slopes with high fire hzrd on ntionl forests in western Montn (verge vlues for thinned plots only): bsl re, number of trees per cre, nd qudrtic men dimeter, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. An exmple of the chnge in hrvest volume for one cse by entry is shown in figure 15. The TB9 prescription did not result in mesurble merchntble volume fter the first entry. This ws true for ll cses nlyzed for ponderos pine both in estern nd western Montn. The gretest volume ws removed from the 50BA prescription during the first entry, nd the volume removed in subsequent entries declined. Trees in ll dimeter clsses were removed during the first entry (fig. 16). In subsequent entries, volume ws lmost exclusively removed in the lrgest dimeter clss (16+ in t d.b.h.). This is firly common result in the other cses for ponderos pine regrdless of ownership, geogrphic loction, or slope clss. Stem biomss volume of trees 1 to 7 in dimeter t brest height As with Dougls-fir, the initil entry for both prescriptions yielded by fr the lrgest volume of trees in the 1- to 7-in d.b.h. clss. Chrcteristic results for the totl stem volume of trees less thn 7 in d.b.h. re illustrted in figure 17. The volume cut in this size clss rnged from bout 160 ft 3 /c to more thn 350 ft 3 /c in the initil entry nd between 50 nd 150 ft 3 /c in subsequent entries (pp. 6, tbles 34 through 37). After the initil entry, the volume of smll trees cut ws generlly lower for the TB9 prescription nd volumes from both prescriptions sometimes fluctuted, but they lwys remined well below the initil volume. Becuse there re few mrkets in Montn for trees less thn 7 in d.b.h., most of this mteril would be either cut nd treted in plce or cut nd left t the lnding. 17

26 Figure 15 Averge merchntble volume projected to be removed from ponderos pine plots on ntionl forests in western Montn on steep slopes with high fire hzrd, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. Figure 16 Averge merchntble volume projected to be removed from ponderos pine plots on ntionl forests in western Montn on steep slopes with high fire hzrd, by tree dimeter t brest height. Averge smll-end dimeter of removed logs Results for verge SED for one ponderos pine cse re shown in figure 18. As with Dougls-fir plots, the TB9 prescription lwys produces logs tht re only slightly lrger thn 5 in on the smll end (5.0 to 5.7 in) (see ppendix 7 tble 39). Processing problems for logs this size were 18

27 Figure 17 Projected nonmerchntble volume in trees 1- to 7-inch dimeter t brest height cut from ponderos pine plots on ntionl forests in western Montn on steep slopes with high fire hzrd, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. Figure 18 Volume-weighted verge log smll-end dimeters for wood projected to be removed from ponderos pine plots on ntionl forests in western Montn on steep slopes with high fire hzrd, by prescription. TB9 = thin from below to 9 inches dimeter t brest height. 50BA = thin from below to 50 percent of bsl re. lredy discussed for Dougls-fir, but the problem is even more pronounced for ponderos pine becuse dimension lumber is poor option for this mteril (Lowell nd Green 2001). 19

28 Log SED increses over time for the 50BA prescription, often verging greter thn 15 in. If logs in these dimeter clsses were to become vilble, they would lmost certinly find mrkets. They re smll enough to be ccommodted by newer hightechnology mills, yet lrge enough, nd in this sitution old enough, tht resonble yields of higher vlued ppernce grdes (prticulrly Fctory grdes) of lumber might be expected from them (Lowell nd Green 2001, Plnk 1982, Willits 1994). As with Dougls-fir, there ws trdeoff between log size nd verge merchntble volume removed. In the exmple shown in figures 15 nd 17, volume removed declined by lmost one-hlf between the first nd the lst entry. This mens tht over time the timber volume removed to mintin low fire hzrd might decrese but the vlue of wood products might increse. Percentge of volume removed by species Ponderos pine ws the most bundnt species removed from the ponderos pine plots (pp. 8, tbles 44 through 47). The results in figure 19 for the TB9 prescription show one of the few entries in ny cse where pine ws not the mjor contributor of removed volume. The results shown for the 50BA prescription re fr more chrcteristic. There ws moderte shift in species becuse the mounts of Dougls-fir nd white woods removed tended to decline rpidly with successive thinnings, so timber removed fter the first entry ws bout 80 percent pine. Finncil nlysis Results from the finncil nlysis re lso similr to those for Dougls-fir. They suggest tht in mny cses the first entry will require subsidy of $100 or more per cre for either the TB9 or 50BA prescription. In fct, ll of the plots treted with the TB9 prescription required t lest $100 subsidy. Except for the first entry, no merchntble volume ws removed under the TB9 prescription, so ctivities under tht prescription lwys hd negtive net returns. The sitution improved over time under the 50BA prescription (fig. 20). During the first entry mix of dimeters were removed (fig. 16), but nerly 60 percent of the plots hd negtive net returns. In the subsequent entries lmost ll of the removed volume ws from trees greter thn 16 in d.b.h. Mny of these entries hd positive net return. These estimtes include the cost of treting mteril tht is not economicl to use for products. They do not include the cost of prescribed fire, which occurs on 30-yer cycle on high-hzrd stnds whether or not plots re thinned. Fires re lso prescribed on 30-yer cycle on low-hzrd stnds, but not until the beginning of the second cycle. The finncil results re summrized for ll cses in ppendix 9 (tbles 52 through 55). Conclusion In this report we demonstrte the use of existing tools nd dtbse mnipultions to evlute fire hzrd tretments for lrge lndscpes. The dt needed to conduct these nlyses re vilble from the USDA Forest Service FIA Progrm for most forested res in the United Sttes. Finer scle nlyses cn lso be performed by using these nlyticl methods if systemtic inventory is vilble. Both TB9 nd 50BA prescriptions improved the fire hzrd rting over the initil conditions, but the 50BA prescription ws more effective. The 50BA prescription further reduced fire hzrd with ech sequentil entry, wheres the TB9 prescription merely lowered fire hzrd rting nd kept it there with subsequent tretments. The residul stnds from the two prescriptions were lso quite different, nd these differences incresed over time. The most noticeble difference ws the ccumultion of bsl re under the TB9 prescription. Over the course of mny decdes, the two prescriptions will crete very different structurl conditions in stnds with identicl initil conditions. The 50BA 20