This section identifies critical factors that require special consideration during the allowable annual cut determination for the Okanagan Timber Supply Area.
When the Timber Supply Analysis Report was completed in 1993, the potential impact of different assumptions on the timber supply forecast was tested by changing the values for certain critical factors in the analysis. Since the analysis, local Forest Service staff have further investigated these assumptions, as well as other critical factors. Their perspectives on several options to partially offset reductions in short-term timber supply are outlined in the following discussion.
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The chief forester must carefully evaluate this information to determine the allowable annual cut and identify where improved information is needed for the next Timber Supply Review. |
• Silvicultural systems - There are two main silvicultural systems used in the Okanagan Timber Supply Area: clearcutting and seed tree. A study in the Coldstream Creek watershed in the Vernon District indicated that using alternative silvicultural systems such as shelterwood and group selection can, over a 60-year period, better satisfy forest cover requirements and therefore lessen restrictions on the rate of cut. Use of alternative silvicultural systems in areas where harvesting is heavily constrained, particularly in community watersheds or areas with high visual quality objectives, could be an effective tool to help offset timber supply shortages due to forest cover requirements.
• Unsalvaged losses - In the timber supply analysis, fire, insects, disease and blow down account for an estimated 126,610 cubic metres of unsalvaged timber losses per year, equivalent to approximately six per cent of the long-term timber supply level. If further salvaging could minimize this loss, or if additional protection methods could be taken, the projected short-term timber supply may be increased. (TSAR page nine)
• Problem forest types - "Problem forest types," including poor timber quality or low timber volume that cannot be economically harvested with current methods, were defined on the basis of available inventory information and existing timber utilization standards. These areas (120,013 hectares) were not included in the timber harvesting land base in this analysis, reducing this land base by 12 per cent. (TSAR page six)
An updated inventory of these specific stands may reveal forest types that could be harvested, perhaps for products that are not currently identified within the existing allowable annual cut, thus increasing current timber supply. In addition, if this harvesting occurred, it may help bring into production good growing sites that are not currently producing a commercial crop of timber thus increasing the long-term timber supply.
• Intensive silviculture - Intensive silviculture treatments, which include spacing, pruning, fertilization, etc., can help improve long-term timber supply levels. The Forest Renewal Plan has allocated nearly half its investment funds toward improved reforestation and tending of forests. The timber supply analysis indicated that the benefits of intensive silviculture treatments—increased timber yields from treated forests, reducing the age at which the trees can be harvested and shortening the regeneration delay period—can increase long-term timber supply levels. However, there is little direct impact on short-term levels. (TSAR page 25)
