Canadian Forest Service Publications
Provincial-Level Projection of the Current Mountain Pine Beetle Outbreak: An Overview of the Model (BCMPB v2) and Results of Year 2 of the Project. 2005. Eng, M.; Fall, A.; Hughes, J.; Shore, T.L.; Riel, W.G.; Hall, P.; Walton, A. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Mountain Pine Beetle Initiative Working Paper 2005-20. 54 p.
Issued by: Pacific Forestry Centre
Catalog ID: 25686
Availability: PDF (download)
The second version of BC Provincial-Level Mountain Pine Beetle Model (BCMPB v2) was developed as part of a two-year project to assess the impacts of mountain pine beetle (MPB), forest management, and interactions between these factors across the province. This report describes the model and the results of the second year of work. The results of the first year of work can be found at http://www.for.gov.bc.ca/hre/bcmpb/year1.htm. The MPB outbreak sub-model is driven by overview infestation maps from 1999 to 2004. The forest management sub-model uses inputs from the forest cover inventory and management information to simulate forestry activities within each timber supply area and tree farm license, including MPB management and salvage harvesting.
We project that the current outbreak will be at its worst in 2006. During that summer 90 million m3 of merchantable pine on the timber harvesting landbase may be killed. Based on the behaviour of the outbreak to date we have no reason to expect that it will kill less than 80% of the pine volume. Nonetheless, there is uncertainty about when and how the infestation will end. We model the assumption that the infestation continues but kills less of each stand than we have observed. We also model the assumption that the infestation ends abruptly at a point earlier than we project as a worst case. Those assumptions have significantly different implications on forest management. The work required to determine which of the assumptions is most likely should be undertaken immediately.
There is significant uncertainty about the length of time that beetle killed wood will be useable for any given product (its "shelf-life"). We modeled differences in shelf-life and found dramatic effects on the amount of timber volume that we will be unable to harvest in a timely manner (non-recovered losses). By 2016 pessimistic assumptions about shelf-life result in 500 million m3 of non-recovered losses whereas optimistic assumptions result in only 200 million m3 of non-recovered losses. Work is currently underway to provide some better estimates of the biological and engineering/manufacturing aspects of shelf-life.
We examine the implications of various alternative harvest levels. Increasing harvest levels reduces non-recovered losses. However, the majority of the susceptible pine occurs in stands where it is mixed with non-pine species. Therefore, if we increase our salvage efforts we also increase our harvest of non-pine volume. For every cubic metre of non-recovered losses that are saved we also harvest 1.3 cubic metres of non-pine volume as an "incidental by-catch".
We observe that, if the volume harvested remains constant, the area harvested increases over the first 8 years of the projection and then decreases over the next 12 years. The reason is that volume per hectare harvested initially decreases as more of the dead pine becomes unusable, and then increases again as harvesting switches from salvage logging of dead pine to the harvesting of non-pine.
We will continue to refine the data and model over the coming year.