Erosion

What is it?  Movement of soil materials by the action of water, wind or gravity

Background  Erosion is a problem when it results from, or is accelerated by our activities  Vegetation and an “intact” forest floor limit erosion potential  Harvesting can lead to erosion problems by removing the canopy and destroying lesser vegetation

Impacts of Erosion  Possible deposition of soil in waterways, damaging fisheries and aquatic ecosystems  Damage to roads, reforested areas and forest stands  Gravitational erosion (landslides) may cause extreme damage to the environment, property, and threat to human life

Impacts of Erosion  Erosion may reduce site productivity by  Displacing forest humus and topsoil layers  Removing or destroying soil structure of fine-textured mineral soils  Preventing plant establishment  Covering top soil layers with subsoil

Sensitive Sites for Erosion  Steep slopes  Wind-deposited soils (dune areas)  Deep alluvial deposits, especially adjacent to major river systems  Water crossings and all riparian areas  Road construction areas (unstable cuts, fills,ditching)

BMP’s for Erosion  Steep Slope Areas  Risk of erosion increases with slope  Even minor rutting may cause erosion problems on slopes  Risk of damage and environmental significance is highest on fine textured soils

 Steep Slope Areas  Preplan skidding on steep rolling terrain  Avoid skidding up and down steep slopes (> 30%) where possible BMP’s for Erosion

 Steep Slope Areas  Winch wood off short slopes, or reach and remove it with a buncher  Dispersed skidding may be preferred to limit the creation of ruts on slopes  Cross-slope skidding may be preferred on moderate slopes with steps (within safety limits) BMP’s for Erosion

 Steep Slope Areas  Avoid skidding through narrow valley drainage ways  Avoid even minor rutting on slopes  Discontinue skidding sooner (e.g., due to wet weather conditions) on hilly terrain BMP’s for Erosion

 Steep Slope Areas  Some timber on steep slopes should be bypassed because of safety, operational and site damage concerns BMP’s for Erosion

 Road Construction  Maintain stable slopes on ditch line, road fills and cuts  Maintain 1:1 sloping of exposed material  Reinforce slopes (re-vegetate or use logging debris)  Crown and grade road surfaces BMP’s for Erosion

 Road Construction  Use energy dissipaters such as boulders, slash, etc. to interrupt water flow in ditches BMP’s for Erosion

 Road Construction  Plan to keep runoff water and sediment away from riparian areas  Use diversions such as tap ditches to direct run off water into areas of undisturbed vegetation or settling ponds BMP’s for Erosion

 Aeolian Soils  Roads and landings built on “blow sand” (aeolian sands) are subject to wind erosion  Limit the size of landings and all areas of exposed soil BMP’s for Erosion

 Aeolian Soils  Cover retired landings, road cuts, borrow pits (road ways) with duff, logging debris or chipper debris  Replant these areas quickly (Pj or Pr)  Avoid heavy site preparation that may promote wind erosion and impede reforestation BMP’s for Erosion

 Deep alluvial soils  Limit the extent of clearcut harvesting (size of blocks, total % of area) on these sites adjacent to large rivers  Plan smaller cuts with prolonged return periods BMP’s for Erosion

 Riparian Areas  Erosion in riparian areas is a significant environmental problem  Adhere to guidelines for riparian areas  Re-vegetate or reinforce exposed soils in crossing areas BMP’s for Erosion

Best Management Practices  Riparian Areas  Manage ditch line runoff to minimize sedimentation  Maintain 100 meter “no grubbing zone” (as per guidelines)  Plan water crossings to take advantage of low slope areas, rocky shores, etc.

Questions?