• Timber productivity estimates for pine plantations
The biological productivity of a forest site determines how quickly trees will grow on that site, what the expected timber volumes from regenerated forests will be, and when these forests will be suitable for harvesting. The most accurate assessments of site productivity are based on the growth of 30 to 150-year-old forests.
Recent studies in the Lakes and Morice Timber Supply Areas that compare growth rates of pine plantations to those of natural pine forests suggest the data used for the base case forecast most likely underestimates timber productivity for pine plantations in the Lakes Timber Supply Area (TSAR page 38). The results of the study in the Lakes Timber Supply Area were not complete when the timber supply analysis was initiated and therefore the new information was not included in the base case forecast.
Tests were completed in the timber supply analysis to evaluate the impacts of the revised estimates on the base case forecast (Figure 11). The predicted increase in timber supply is due to a reduction of two to four years in the time required for pine plantations to grow to the minimum green-up* height, a significant reduction in the minimum harvest ages for pine plantations growing on medium and poor quality sites, and an increase in the timber volume that can be harvested from these forests. A separate test assessed the impacts of applying the new information to the integrated resource management zone only, because it is expected the integrated resource management practices required on the remainder of the timber harvesting land base will not permit all the intensive management practices, such as site preparation and planting, necessary to achieve the higher productivity estimates. (TSAR page 38)
Figure 11 Impacts of changing the timber productivity estimates for pine plantations
• Increased timber utilization
Current management standards require that all timber of commercial species that meets or exceeds specified size limits and is suitable for lumber and pulp chips be removed from within cutblocks. It is common for the minimum size requirements for lodgepole pine to be smaller than for other species (15 centimetres at stump height versus 17.5 centimetres for other species).
In the Lakes Timber Supply Area, timber companies have indicated they are currently utilizing more wood than required. This may result in more volume being removed from harvested areas than is currently predicted by the timber supply analysis, potentially increasing the short- and long-term timber supply.
• Size of the timber harvesting land base
In the Lakes Timber Supply Analysis, environmentally sensitive areas and forests not traditionally harvested were deducted from the timber harvesting land base. Changes in harvesting and reforestation technology and relatively high timber markets may make some of these forests economical to harvest in the future.
A test completed in the timber supply analysis indicates a five per cent increase in the timber harvesting land base allows the current allowable annual cut to be maintained for 100 years, 30 years beyond the base case forecast. (TSAR page 30)
• Intensive silvicultural treatments
In some circumstances, intensive silvicultural treatments such as juvenile spacing or fertilization that increase tree growth and the long-term timber supply may also increase the short-term timber supply. As the Timber Supply Review was designed to assess the timber supply impacts of current practices, the range of intensive silvicultural treatments that might be implemented in the Lakes Timber Supply Area was not examined. Further analyses are required to examine the potential opportunities for intensive silvicultural treatments and the implications of those treatments on timber supply and other resources.
• Commercial thinning
Approximately 11 per cent of the pine forests within the timber harvesting land base are between 40 and 80 years old and may be candidates for commercial thinning. However, to date very little commercial thinning has occurred in the Lakes Timber Supply Area. Commercial thinning has the potential to supply some additional timber in the short term. Further study is required to identify candidate forests for commercial thinning, to examine the feasibility of a commercial thinning program, and to assess the impact of this practice on the projected short- and long-term timber supply.
