Riparian Thinning LogicRiparian Thinning LogicJack Sleeper - Siuslaw National ForestJack Sleeper - Siuslaw National Forest
March 20, 2008March 20, 2008
Talk OutlineTalk Outline
• Riparian Processes
• Human Impacts to Riparian Areas
• Siuslaw NF Thinning Design and Effects
Large TreesLarge Trees
Debris Debris FlowsFlows
Wood & Sediment from Debris Flow Wood & Sediment from Debris Flow
Upper Green River LandslideUpper Green River Landslide
Valley Floor Buried with Landslide DepositValley Floor Buried with Landslide Deposit
Beaver PondsBeaver Ponds
FloodsFloods
Spruce & Alder Seedlings
Natural Conifer StandsNatural Conifer Stands
• Large diverse tree species
• Disturbance & competition limit dense conifer stands near streams
• Conifer stands mostly on toeslope and high terraces
• Trees/Acre-lowest in riparian areas and increase upslope
• Conifer stands have irregular riparian edges
Large Wood in Streams
Riparian Impacts
Settlement Reduced Large Treesin Riparian Areas
Large Trees Removed
Cape Perpetua
Florence
Roads Disconnect Riparian Area from StreamRoads Disconnect Riparian Area from Stream
Debris Flow Intercepted by Road
Tenmile Creek
Stream Cleaningfor
-Transportation-Fish Passage-Cedar Shakes
Natural & Managed Natural & Managed Riparian StandsRiparian Stands
• Natural Stands– Large conifer with few trees/acre– Diverse species– Understory shrubs and trees present
• Managed Stands– Small conifer with many trees/acre – Mostly Douglas-fir– Understory shrubs and trees absent
Why Thin Close To Streams?Why Thin Close To Streams?
• Large wood has a major influence on aquatic processes and habitat
• Large diameter conifers near streams have been reduced
• Large wood in streams and on floodplains reduced
• Thinning accelerates development of large diameter trees and diverse tree species
• Northwest Forest Plan, Endangered Species Act, Essential Fish Habitat
Riparian Thinning Design and Effects
Interdisciplinary Interdisciplinary Team Team
Plans Plans Restoration Restoration Activities Activities
Including Including ThinningThinning
Thinning ConcernsThinning Concerns
• Stream Temperature
• Stream Sedimentation
• Wood Recruitment to Streams
• Windthrow
Stream Buffer DesignStream Buffer DesignVariable widthVariable width
– Based on site specific conditionsBased on site specific conditions– Follows edge of dense plantation Follows edge of dense plantation – Protect Unstable AreasProtect Unstable Areas
• Perennial StreamsPerennial Streams– First 2 rows of conifer near stream-no cut– Minimum 30 ft no cut buffer from floodplain
• average 50-80 ft
• Intermittent StreamsIntermittent Streams– First row of conifer near stream-no cut– Minimum 15 ft no cut buffer
Stream Stream No Cut | ThinNo Cut | Thin
Thinned Unit No Cut BufferThinned Unit No Cut Buffer
Stream Shade from No Cut BufferStream Shade from No Cut Buffer
Dense Vegetation ShadesDense Vegetation ShadesSmall StreamsSmall Streams
SedimentationSedimentation
Wood Wood RecruitmentRecruitment
UnthinnedUnthinned 100 Trees/Acre100 Trees/Acre 60 Trees/Acre60 Trees/Acre 30 Trees/Acre30 Trees/Acre
Douglas-fir Stand Development in Western OregonSeven Years After Thinning and Underplanting
UncertaintyUncertainty
• Thin Density-trees/acre– Thin heavy or light?– Distribution across the landscape
• Down Wood– Small pieces now or larger ones later?
• Windthrow
• How to contract & fund complex design?
• Climate Change
Commercial Thinning Funds Commercial Thinning Funds other Restoration Activitiesother Restoration Activities
Precommercial Thinning
Riparian PlantingRiparian Planting
Conifer ReleaseConifer Release
Add Large Wood Add Large Wood to Streams & to Streams & FloodplainsFloodplains
Road DecommissionRoad Decommission
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