The technical critique states "the timber supply analysis of the Fraser TSA [Timber Supply Area] published in the Timber Supply Review has been confirmed."
However, the critique contends that the growth-and-yield projections used in the Forest Service analysis for regenerated forests are conservative because:
• the timber productivity estimates (site indices) are based on existing over-mature forests and are lower than would be expected for regenerated forests on the same sites
• the effects of density and competition control treatments are not considered
• the effects of regenerating more productive species through planting in areas previously occupied by less productive species are not incorporated.
Using different projected timber yields for regenerated forests results in a timber supply forecast that "is the same as the baseline scenario (in the Forest Service analysis) up to year 30." After this point, timber supply levels are predicted to be above the base line forecast. This issue is also raised in several of the timber industry submissions.
According to the critique, neither of the main factors which limit the short-term timber supply are related to current management practices or how they were modelled in the Timber Supply Review. These factors are:
• the forest cover requirements, which are based on the practices which limit the amount of a given area that can be harvested at any time to meet integrated resource management objectives, and,
• a shortage of mature timber in 105 to 115 years due to the pattern of past harvesting.
These factors make it impossible to increase short-term supply through increased timber yields from regenerated forests.
Forest cover requirements are a major factor in the timber supply forecasts for the Fraser Timber Supply Area. In the short-term, reduced requirements in the integrated management zone did not increase the projected short-term timber supply. However, increased requirements caused a 65,000 cubic metre per year reduction in supply below the base case forecast during the first decade.
The critique makes the following recommendations about the actual current practices:
• the use of forest cover requirements to model the operational rate of harvesting "should be re-examined"
• candidate forests for commercial thinning should be identified, and
• "assignment of visually sensitive zones in the land base must be validated and agreed upon...(and) the forest cover requirements assigned to these areas must be assessed to ensure they are reasonable in light of the impact they place on timber supply"
With the exception of suggested changes in the timber productivity estimates for regenerated forests, recommendations were not provided to improve the data, assumptions or computer model used in the Forest Service analysis.
