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Tree Farm Licence 45



Enhanced silviculture

In MP No. 3, Interfor has committed to develop a program of enhanced silviculture. Accordingly, the analysis includes a harvest forecast which shows the timber supply implications of enhanced silviculture activities which the licensee describes as 'currently implementable'. These activities include the use of genetically improved seedlings to increase yield from regenerated stands, the regeneration of stands to species which are expected to have a higher yield, and the harvesting of existing managed stands at younger ages than the minimum harvestable age. For the sensitivity analysis, it was assumed that: genetic gains would range from a 2 to 5 percent increase in volume, depending on the species group; all Douglas-fir stands would be regenerated to higher-volume hemlock and balsam stands; the minimum harvestable age of all stands regenerated with genetically improved stock on good-productivity sites would be decreased by 10 years, and finally, that site indexes would be adjusted by 6 metres for cedar and 3 metres for other species. The analysis shows that if all of these silvicultural improvements are made, the initial harvest level projected in the base case could be maintained for 6 decades, followed by a 5-decade transition period during which the harvest level would first decrease, then increase to reach a long-term harvest level of 248 100 cubic metres (28 100 cubic metres higher than the initial harvest level). The bulk of the effects can be attributed to the site index adjustment; the remaining adjustments affect only medium- and long-term timber supply. As discussed under site productivity estimates above, I do not believe there is firm statistical basis for site index adjustments for all species and all ages. In that section I concluded that site index adjustments exert an unquantified upward pressure on timber supply in the medium to long term. Here I will consider only effects attributable to enhanced silviculture.

The sensitivity analysis is likely conservative in its assessment of potential effects of silvicultural enhancements since the impact on green-up ages resulting from genetic improvements was not modelled. Also, Interfor asserts that it is likely that the minimum harvestable ages could be reduced for medium and poor sites as well, and in this respect, the assumptions modeled in this sensitivity analysis are conservative. Offsetting these effects somewhat is the fact that the site indexes were not adjusted with species conversion from Douglas-fir to hemlock, which would involve a small site index reduction.

This scenario indicates that enhanced silviculture could provide more timber supply in the medium to long term for this TFL than indicated in the base case, which could provide some flexibility to offset downward impacts in the medium term. However, there is no commitment to this management regime in MP No. 3, and no verification that the projected increased yields can be achieved. Therefore, I do not accept this sensitivity analysis as a more appropriate representation of timber supply than the base case. Until commitments are made, and more conclusive evidence is available, I will not adjust my view of timber supply on account of potential actions and effects. In the meantime, I recognize that many of the base case assumptions can reasonably be characterized as conservative and encourage the licensee to pursue silvicultural activities that could very well improve the timber supply projections for this unit.

Two more enhanced silviculture scenarios are described in the timber supply analysis. One is characterized by Interfor as 'feasible pending verification'. In this scenario, in addition to the silviculture enhancements outlined in the 'currently implementable' scenario, stand volumes are increased, future road reductions are decreased, the operable land base is increased, alder stands are converted to coniferous species, high intensity areas for timber management are established, and commercial thinning is conducted. The final enhanced silviculture scenario examines opportunities which 'require development prior to implementation', including fertilization gains, increased harvesting in environmentally sensitive areas and riparian reserves, and selective harvesting in visually sensitive areas. The timber supply impacts of these two scenarios were not examined in the analysis, and I have assumed no contribution to timber supply from the activities described in these two scenarios in my determination. However, I accept that these scenarios suggest that some timber supply flexibility may be gained in the future if additional enhanced silviculture activities are implemented.

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