The current management practices that are approved and implemented in each zone are briefly described below.
• Wildlife/biodiversity - Deciduous trees in mainly coniferous forests and in deciduous forests are excluded from the timber management land base. Live trees and short, dead trees that provide wildlife habitat are left in many areas following harvesting and represent a small annual reduction in available timber.
• Water management - To protect water quality and flow levels in all zones outside the community watershed zone, harvesting is limited so that no more than 30 per cent of an area is permitted to be harvested and reforested with trees less than three to five metres tall at any time. The minimum height for acceptably reforested areas varies in each management zone. In areas that have been harvested more than this practice permits due to salvage of mountain pine beetle infested timber, the analysis precluded further harvesting until reforested areas reached the minimum heights.
• Basic silviculture - By law, harvested areas that are expected to produce timber in the future must be reforested with ecologically acceptable species within a specified time period. In the Boundary Timber Supply Area reforestation is achieved by a combination of natural regeneration and planting, with regeneration delays of three to seven years. Mixtures of lodgepole pine and other species are being encouraged to reduce the risk of mountain pine beetle outbreaks. Areas reforested since 1984 are assumed to be managed forests with faster timber growth rates than unmanaged forests.
• Harvest ages - Minimum harvest age is defined as the time it takes for stands to grow to harvestable size. The minimum harvest ages used in the timber supply analysis range from 60 to 120 years based on site productivity and current management practices. Due to the mountain pine beetle, pine stands as young as 60 years are currently being harvested.
• Harvest priority- Until 1993, up to 80 per cent of the allowable annual cut was harvested from lodgepole pine forests that were susceptible to the mountain pine beetle. Because beetle populations have declined, currently only 50 per cent of the allowable annual cut is from pine stands at risk of beetle attack.
• Timber utilization - Within cutblocks, timber that meets or exceeds the following size limits and is suitable for manufacturing lumber is considered merchantable and must be utilized:
• logs from trees must be at least 50 per cent usable
• tree diameters at chest height must be 12.5 centimetres for lodgepole pine and 17.5 centimetres for other species
• top diameter of cut logs is 10 centimetres
• Soil conservation - Road building and harvesting layout follow provincial guidelines. It is estimated that 3,300 hectares (less than one per cent of the productive forest land base) is occupied by roads, skid trails and landings which are considered non-productive and which have been deducted from the timber management land base. Over the long term, construction of roads, skid trails and landings is expected to reduce the timber management land base by about 12,300 hectares or approximately three per cent. Actual losses may be higher than estimated depending on the harvesting methods used.
• Unsalvaged losses - Forest losses due to wildfire, insects, diseases and blowdown are minimized as much as possible. Current management practices are estimated to maintain unsalvaged losses to an average of 50,400 cubic metres per year from the following sources:
• wildfire - 3,500 cubic metres
• blowdown - 5,000 cubic metres
• insects - 5,800 cubic metres
• wildlife habitat and seed trees - 6,100 cubic metres
• root rots - 30,000 cubic metres
Estimating losses for root rot is especially difficult. Actual future losses may be higher or lower than estimated.
