The Forest Service timber supply analysis projects that the current harvest level can be maintained for 20 years. According to the analysis submitted by the major licensees, this is conservative, based on the assumptions listed below.
Growth and yield estimates
Future stand volumes have been underestimated in this review because the site index equations underestimate the site indexes of overmature stands and overestimate the time required to achieve "green-up."
Another reason cited for underestimated future stand volumes is the higher operational adjustment factor of 15 per cent. A new standard, developed after the Forest Service analysis was conducted, produces a lower operational adjustment factor and increases future volumes.
Minimum harvestable age
The licensee analysis recommends that future timber supply analyses consider minimum volume per hectare, minimum stem diameter and culmination age in determining minimum harvestable ages.
Timber harvesting land base
Some operations occur within inoperable areas that should be included in the timber harvesting land base for future analyses.
Roads, landings and skid trails
The 12.8 per cent land base deduction for existing roads, landings and trails is excessive; the actual figure is closer to 9.1 per cent. The analysis also contends the estimate of 7.6 per cent for future roads, landings and trails is too high; 5.2 per cent would be more appropriate.
Regeneration assumptions
The quantities of balsam, cedar and hemlock regeneration incorporated into the Forest Service analysis exceed current practice.
The licensee analysis also states the regeneration delay periods are too long for some species. It reduces the regeneration delay for these species so that the same regeneration delay is used for all species except naturally regenerated lodgepole pine.
Selection harvesting
The volume estimate for selection management is low.
Unsalvaged losses
Unsalvaged losses have been overestimated in the Forest Service analysis. The volume reduction for wildlife trees is unnecessary, as current practice is to utilize deciduous trees for wildlife trees and top snags for wildlife stubs, neither of which have an impact on the merchantable inventory. In addition, the losses to Hemlock Looper have been double-counted through the volume removal under unsalvaged losses, and the removal of the hemlock volumes of Class 8 and 9 stands from the timber harvesting land base.
The licensee analysis also maintains there will be fewer unsalvaged losses as access improves, but that the Forest Service analysis does not take this into account.
Ungulate winter range
The actual harvesting constraint in this zone is overestimated because selection harvesting areas, which already meet green-up requirements, are interspersed within this zone.
Community watersheds
The weighted green-up height for community watersheds should be 4.8 metres instead of the 5.4 metres specified in the Forest Service analysis. This is based on a six-metre hydrologic green-up height in the upper 60 per cent of the watershed as opposed to the seven-metre green-up height used in the Forest Service analysis.
Harvest passes
The licensee analysis asserts the method of applying the number of harvest passes in the Forest Service analysis is incorrect as it assumes that each pass harvests the same area. The actual limitation is that not more than 30 per cent of the area should below three metres in height.
The licensee analysis also makes the following comments regarding the Forest Service analysis:
• the amount of lodgepole pine harvested in its early stages is underestimated due to the "oldest first" approach to harvesting
• local adjustments should not have been made to the harvest profile in developing the analysis unit distribution of not-satisfactorily-restocked area
Since the data was collected for the Forest Service analysis, the Kamloops Land and Resource Management Plan has been approved and specific problem forest stands have been designated to Pulpwood Agreement 16. These initiatives are now current management and are incorporated into the licensee analysis. Based on this information, the licensees conclude that the current harvest level can be maintained for 80 years.
