As part of the provincial Timber Supply Review, the British Columbia Forest Service has examined the availability of timber in the Merritt Timber Supply Area (TSA). This analysis assesses how current forest management practices affect the supply of wood available for harvesting over the next 250 years. It also examines the potential changes in the timber supply stemming from uncertainties about forest growth and management actions. It is important to note that this report only examines timber supply implications of current practices and uncertainty. As such, the forecasts should be used for discussion purposes only; they are not allowable annual cut (AAC) recommendations.
The Merritt TSA consists of approximately 1.12 million hectares, of which about half a million hectares are considered available for timber harvesting under current management practices. The present AAC for the TSA is 1 204 250 cubic metres per year, excluding woodlot licences and non-replaceable timber sale licences.
While much of the TSA is managed according to integrated resource guidelines, approximately 31% of the land base available for timber harvesting has special management requirements for wildlife habitat and visual quality. Specific forest cover objectives have been established to account for these values. About 19% of the area available for harvesting is managed under a selection management regime.
The base case harvest forecast for the Merritt TSA has a starting harvest level of 1 204 250 cubic metres per year. Given current management assumptions, the initial harvest level can be maintained for 110 years. This is because of an abundance of mature forest. Approximately 77% of the TSA's timber harvesting land base is or soon will be available for harvest. After 110 years, the harvests begins to decline by 7% per decade until the long-term harvest level of 925 000 cubic metres per year is reached 140 years from now.
Much of the data and assumptions used in the analysis are subject to varying degrees of uncertainty. Sensitivity analyses were used to determine how data and assumptions impact the results of the timber supply analysis. Since there is an abundance of mature forest within the TSA, the first 8 decades of the harvest forecast is unaffected by any of the changes examined in the sensitivity analyses.
Increasing or decreasing to the volume estimates for existing
stands, the size of the timber harvesting land base, or the amount
of area covered by mature forests has the greatest impact on the
length of time the starting harvest level can be maintained.
The long-term harvest level is sensitive to volume estimates for
regenerated stands, increasing or decreasing the size of the timber
harvesting land base, longer or shorter regeneration delays, and
increasing or decreasing green-up cover guidelines.