As part of the provincial Timber Supply Review, the British Columbia Forest Service has examined the availability of timber in the Sunshine Coast Timber Supply Area (TSA). The analysis assesses how current forest management practices affect the supply of wood available for harvesting over both the short (next 20 years) and long (next 250 years) term. It also examines the potential changes in timber supply stemming from uncertainties about forest growth and management actions. It is important to note that the various harvest forecasts included in the report indicate only the 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 Sunshine Coast TSA consists of about 1.1 million hectares, of which about 224 000 hectares are considered to be suitable and available for timber harvesting. The total volume of standing timber in the area is about 70 million cubic metres, of which about 55 million cubic metres is old enough to be harvested. Forests in the area are dominated by stands of Douglasfir, western hemlock and western redcedar. The current AAC for the Sunshine Coast TSA is 1.1 million cubic metres per year.
The results of this timber supply analysis indicate that, given current forest management assumptions, the current AAC can be maintained for the next 10 years before declining by 10% per decade to 876 000 cubic metres per year is reached in approximately 30 years. This rate of harvest, which is 11% below the steady longterm harvest level, must be maintained for approximately 100 years in order to avoid further timber supply shortfalls in the future. In approximately 130 years, after most of the forest is comprised of managed stands, the rate of harvest can be increased to the steady longterm harvest level of 986 000 cubic metres per year.
The above results reflect current knowledge and information on forest inventory and growth. However, it is important to recognize that uncertainty exists about several of the factors that define timber supply. A series of sensitivity analyses indicate that these uncertainties can affect timber supply to varying degrees.
Two important factors affecting the harvest
forecast in the Sunshine Coast TSA are forest cover requirements
used to manage for visual quality of the landscape and the estimated
site indices of the regenerated stands. Uncertainties in either
of these factors affect the harvest forecast in both the short and
longterm. In general, sensitivity analyses indicate that,
for the same amount of change in a factor (e.g., plus or minus
10%) to an uncertain assumption or piece of data, indicated decreases
in the harvest forecast were generally larger than indicated increases.