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This project will estimate stand level losses due to the spruce bark beetle (SBB) across British Columbia (BC). Mapping estimates will be created for all areas with current stands and potential future stands across BC. Results will be incorporated into decision support tools. The spruce beetle, Dendroctonus rufipennis (Kirby) occurs throughout the range of spruce, Picea spp., in North America. In the west, Picea Engelmannii, P. glauca and P. sitchensis are principal hosts (Furniss and Carolin 1977). Under endemic conditions this beetle is present in small numbers, attacking weakened trees or trees that are downed by wind, or in slash. However, sporadically, major outbreaks occur which kill thousands of trees in western North America, including BC and Alaska. Normally this insect has a two year cycle, but at higher elevations or latitudes a 3 year cycle is common. New adults emerge during August to October, from killed trees after spending 2 or 3 years under the bark and move to attack the lower bole and root collar of new host trees. Recent outbreaks in Alaska?s Kenai Peninsula have been linked to above-normal temperature years, particularly in the summer (Berg 2000). This massive outbreak killed nearly every mature spruce tree on the Kenai. Most of the attacked trees were more than 100 years old. The mechanism triggering outbreaks is not clearly understood but it is believed that warmer climate accelerates the insect life cycle to less than 2 years. In addition, warmer and drier climates may induce stress on trees, which are less likely to successfully defend against this beetle. Spruce trees defend themselves against beetle attack by producing copious resin which drowns eggs and young larvae. Spruce bark beetle (SBB) is a more difficult organism to model than mountain pine beetle (MPB) due to complexities and variability in its life cycle. We do not know enough at this point about SBB entomology and spread dynamics to construct a population spread model for SBB, although new techniques are evolving (e.g., Landes et al., 2003). From what we do know about SBB, how it has spread over recent decades (Zhang et. al., 1999), and about the relationship between MPB and climate, it is reasonable to postulate that there is a significant relationship between SBB and climate (Woods et. al, 2004). Like its relative, the mountain pine beetle, the spruce beetle is also killed by temperatures below -35 or -40 degrees C. A technique that may be utilized to take the first step towards understanding the potential effects of climate change on SBB stand-level losses is physical envelope modeling, an empirical method recently used by Hamann and Wang (2005, 2006) and Wang et al. (2006) to study BC forest impacts under future climates. The stand-level loss estimates, then, may be used to consider adjustment of management practices through bio-economic modeling (Eisenworth and van Kooten, 2002). The project will start by compiling empirical data about the potential impact of SBB in reducing recoverable timber across BC. Specifically, the climatic conditions such as variations of 30-year averages of monthly minimum and maximum temperatures and precipitation for both occurrence of SBB and outbreaks of SBB will be defined by analysis of geographic SBB occurrence data and climate data (Wang et al. 2006). It is in this step that SBB entymological expertise of Alfaro and Taylor will be incorporated. Because of the nature of such 'climatic suitability? mapping, a first-order relationship between climate and white spruce, as well as climate and SBB will be appropriate. Once climate-SBB relationships are determined, then tools such as ClimateBC (Wang et al. 2006) will be used to create future projections of climate and stand-level SBB impacts for the next century. Subsequently, climate variables from all available climate models and experiments will be extracted. A set of projections representing the 10th, median and 90th percentile values will be compile ...
Keywords: Forest, Investment, Account, (FIA), Dendroctonus, Rufipennis, British, Columbia
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