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

20022002 20032003

20062006

20022002 20032003

20062006