The Decline of Aspen in CA

Transcription

1 // Effects of Logging ear Streams to Restore Riparian The Decline of Acreage in Western States. K.W. Tate UC Davis. -% B.E. Jones USFS USFS Lassen F USFS Region University of California Presented March, Susanville, CA Millions of Acres % -% -88% -9% -% -% CO UT M WY AZ ID MT current historical Bartos. Rocky Mountain Research Station s Forest Inventory and Analysis Project. The Decline of in CA Conifer encroachment reduces recruitment, leads to stand decay Lassen F ELRD. % % > stands inventoried. ~,7 stand acres. <% of district area. 8% Risk Factor % Conifer encroachment 9 Excessive browse Risk of Stand Extinction High Moderate Low Jones et al., In prep. Lassen ational Forest Ecological Importance Keystone Species? Supports a large number of plant, insect, avian, and mammal species. Kuhn et al. associated aspenmeadow-conifer forest sites. with <% conifer cover. Biodiversity nd only to riparian areas in western US. Sierra evada & Cascades oasis of diversity in a coniferous landscape. Shannon-Weiner Diversity..... a (.) b (.) a (.) Sheppard et al.. Conifer Meadow Community Type p <.

2 // Dissimilarity Among Community Types Jaccard's Index of Dissimilarity Forest.8 Meadow.77 (8. ) Forest.98 Meadow Sørensen's Index of (7.7 Forest Meadow ) Forest.9 Meadow Meadow (9.8 ) Conifer Meadow Conifer Many riparian aspen stands are encroached by conifers. Conifer removal is an effective release strategy. % Dissimilarity = (- Jaccard s) Jones et al. Restoration Ecology Some Concerns Reduce stream canopy cover? Increase stream temperature? Degrade water quality and aquatic habitat? Compact soils? o impact? Short term impact? Long term gain? Test Concerns Lassen F. Significant conifer encroachment. Active aspen restoration program. Collaborative study to evaluate possible water resource impacts. Study Sites - LF Summer enrolled projects in a study Lassen ational Forest Eagle Lake Ranger District Pine and s - Jan - Aug - Jan 8 Hat Creek Ranger District Bailey Creek - Sep

3 // Study Timeline General Study Design: Above/Below, /Control, Before/After Data Collection Begins August Pine/Bogard January Pine/Bogard Data Collection Ends Control Reach 8 January Pine/Bogard September Bailey Final Analysis in Progress Control Stand Stream monitoring stations Reach Stand Soil bulk density sampling areas Soil moisture monitoring stations Data for this presentation: Pine, Bogard, Bailey Creeks Data from to June 8 Jan Pine/Bogard Aug Pine/Bogard Sep Bailey Stream Canopy Cover Stream Temperature Water Quality Soil Compaction Pine Creek.7 mile Elevation: ft Jan Jan ~ Acres, Pine Cr. ~,8, Bogard Cr. ~, Over snow protect soil Whole tree reduce slash End-line to within 7 ft of stream to protect riparian areas. Track-laying harvester, rubber tire skidders..7 mile

4 // Jan Spring of Aug Acres, Pine Cr. ~,8, Bogard Cr. ~,7 Late harvest dry soils, further reduce slash Whole tree reduce slash Variable distance from stream based on slope, ground cover, etc. to ft. Track-laying harvester, rubber tire skidders..7 mile Aug and Sep Harvests Sep ~ Acres, ~, stream Late harvest dry soils, further reduce slash Whole tree reduce slash Variable distance from stream based on slope, ground cover, etc. to ft. Track-laying harvester, rubber tire skidders.. mile Elevation: ft Canopy Cover and Solar Input Test for change in treatment reaches before and after each conifer removal project sample site every to ft BO Pine/s Jan Significant stream canopy cover reduction due to conifer removal (P<.). Bogard -% Pine -% PC BO PC Solar Radiation % Canopy and Available S Canopy Jun 8 Jul Aug Sep

5 // Pine/s Aug o significant stream canopy cover reduction due to conifer removal (P=.) Bailey Creek Sep Significant reduction due to conifer removal (P<.), -7% BO PC BO PC8 Canopy Cov ver (%) Pine Creek - Site 8 to 8 - Site to 8 Before After Time Period Relative to Aug Fall Phase BR BR % Canopy Cover over Stream Pre- ** 7 Post- upstream sample site Stream Temperature Test for change between up- and down-stream sites before and after conifer removal downstream sample site PC Pine Creek Jan % less canopy PC Max stream temperature above (PC) and below (PC) 7 F o post Jan treatment Jan - cut 7 PC post Aug treatment PC 7 8 Julian Day BR Bailey Creek Sep 7% less canopy Max stream temperature above (BR) and below (BR) BR 7 BR BR ng Maximum (F) 7-Day Runni 7 7 post Sep cut Julian Day 7 7 o water chemistry changes were detected Pine Creek ( to 7): 8/ (7%) samples analyzed for O - were <. mg/l, mean of detects was. mg/l. / (98%) samples analyzed for H - were <. mg/l, mean of detects was. mg/l. 9/ (77%) samples analyzed for PO -P were <. mg/l, mean of detects was. mg/l.

6 // o sediment or turbidity changes were detected. Example: Bogard Creek, turbidity Turbid dity (ntu) post Jan harvest o macroinvertebrate changes were detected Example: Bailey Creek Sep Metric 7 pre pre post o. Families. BO BO post Aug harvest 7 B B B B B Diversity... % Tolerant % Intolerant 7 Sample Site (upstream to downstream) Soil Compaction - Bulk Density Test for change before and after conifer removal Pine Creek Permanent sample areas. and control. to in, and to in depth. Pine/Bogard Aug Volcanic soils. Soil surface (p=.) Subsurface (p=.88) Soil bulk density was not increased. nsity (gm/cm ) Bulk Den. control treatment to to Does not include skid. trails or landings.. Pre-Treat. () Post-Treat. () Bailey Creek Sep Volcanic soils. Soil surface (p=.) Density (gm/cm ).8... Subsurface (p=.). Soil bulk density was not increased. Does not include skid trails or landings. Dry Soil Bulk D. control to inch treated to inch Pre- Post () (7) Conifer removal to restore riparian aspen stands:. Variably reduces canopy and increases solar load to stream. Will aspen fill the gap?. o apparent changes in stream temperatures, chemistry, or sediment.. o changes in key macroinvertebrate metrics change in functional feeding groups?. o changes in soil surface or subsurface bulk density. To ~ feet

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