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Blue Mountains Forest Plan Revision Developing Long-term Sustainable Yield and ASQ Estimates December 2009. Long-term sustainable yield. Long-term sustainable yield is the highest uniform wood yield from lands being managed for timber production (land is at the desired condition).
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Blue Mountains Forest Plan RevisionDeveloping Long-term Sustainable Yield and ASQ EstimatesDecember 2009
Long-term sustainable yield • Long-term sustainable yield is the highest uniform wood yield from lands being managed for timber production (land is at the desired condition). • Depends on values and conditions that you want to sustain through time. • Needs to be framed by laws and biological capability of land.
ASQ • Allowable Sale Quantity. The quantity of timber that may be sold from the area of land suitable for timber production covered by the forest plan for a time period specified by the plan. This is based on the existing condition of the land.
ASQ and the long-term sustainable yield can vary by alternative in the EIS. • They both depend on the amount of land suitable for timber production in each alternative. • Timber production is the “purposeful growing, tending, harvesting, and regeneration of regulated crops of trees… for industrial or consumer use.”
Determining Areas Unsuitable for Timber Production Criteria include: areas where irreversible damage could occur, regeneration is not assured within 5 years, non-forest, land that has been withdrawn from production, unsuitable based on other multiple-use objectives. Areas identified as unsuitable for timber production in the proposed action include: wilderness, non-forest, riparian areas, old forest, roadless areas, and specially designated areas.
Process for Volume Estimation • Develop desired conditions • Stratify the landscape by existing condition • Determine areas suitable for timber production • Group inventory data by the stratification • Grow/model inventory data through time • Apply model results to strata acres
Long-term sustainable yield Timber suitability map and modeled inventory plots (yield of prescription at desired condition) were used to estimate the long-term sustainable yield.
Allowable Sale Quantity The timber suitability map, existing conditions, and forest succession model were used to generate the allowable sale quantity. • Succession Model Components: • Vegetation type • Structure type • Disturbances (fire, insects, disease) • Treatment type • Harvest volume • Succession rates • Time
Volume Yields for the Proposed Action(million board feet per year)
Annual Growth and Mortality for Timber Suitability Groups (board feet per year) 400,000,000 350,000,000 300,000,000 250,000,000 Mortality Volume 200,000,000 growth 150,000,000 100,000,000 50,000,000 0 Timber suitability Blues Current Growth and Mortality Red= Unsuited for timber production Yellow = Suitable for harvest but not production Green = Suitable for timber production