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Mountain pine beetle impacts and risk projections in young lodgepole pine stands
Maclauchlan, Lorraine E.
Of the 15 million ha of lodgepole pine in British Columbia, approximately 2 million ha are between 20-55 years of age with over 1 million ha between 20-35 years (MOFR 2005). These stands represent future harvests, habitat and forest structure. Many young stands are currently being impacted by the MPB and associated bark beetles. The risk from MPB to our mid-term future forest inventory is a major concern to both forest industry and government. Tools to determine where the most severe damage is occurring, to what extent attack is observed, and how long the risk will persist, are greatly needed. Historically, young or small diameter lodgepole pine becomes a ?sink? for MPB during the declining phase of an outbreak. A beetle ?sink? describes trees or stands that are not normally highly susceptible to MPB due to age or size, and generally few, or no MPB brood develop successfully within attacked trees under these conditions. The current outbreak has produced exponentially greater MPB populations over the landscape, and consequently the phenomenon of young stands becoming a ?beetle sink? could result in the devastation of the majority of young pine stands greater than 20 years old prior to the collapse of the outbreak. Two FIA-FSP projects (Y06-1003 and M07-5009) were initiated in 2005 and 2006 to study several aspects of the phenomenon of MPB attacking young stands. They are very closely linked with the first project primarily evaluating and quantifying MPB attack levels in young stands throughout the core of the outbreak area. The second project involves developing a risk rating system incorporating GIS overlay analysis techniques with the data generated from the first project. More than 3,500 stands have been aerially assessed over the two years (2005-2006) and the impact of MPB in young pine stands ranged from no impact or <1% red attack to >90% visible red and grey attack. Preliminary results from these projects show a significant increase over the two years in the total number of polygons having some level of MPB attack: 49% in 2005 increasing to 71% in 2006. Cumulatively, these projects have quantified the impact of MPB in 20-55 year old lodgepole pine stands for districts within the core outbreak area which include: Nadina, Prince George, Vanderhoof, Quesnel, Central Cariboo, 100 Mile House and portions of the Chilcotin. Reduced assessments (ground only) were conducted south of 100 Mile House because MPB attack in younger stands has only just started in these more southerly districts. The end product of this work will be the development of a model to predict the risk to remaining young pine stands. We need to build on these results by testing this ?projected risk? model through ground and air-truthing of select stands in 2007. We plan to sample stands throughout the full range of the outbreak, focusing more in the south within the Kamloops, Okanagan Shuswap and Cascades Districts. The proposed project will use the data collected from 2007 air and ground surveys to calibrate the model and create new projections for stands throughout the core outbreak area and southern portions of BC. The work proposed for 2007 will determine the ultimate condition and stocking of highly impacted stands as well as delineating those stands less impacted and the likelihood of future impacts. The risk model developed will be utilized to predict a number of parameters for each stand based upon its geographic location in BC, stage of outbreak (declining, static, new, building), and adjacent and future risk (as determined in 2005-2006 aerial surveys). The risk parameters to be tested include: likelihood of 2006 and 2007 MPB attack; 2006 impact (% red attack); 2007 impact (% green attack); and, probability of future attack. This 3rd year of data collection, parameter testing and evaluation will confirm projections of impact in young stands (timber supply losses) and provide more reliable loss estimates to expect between now and the projected coll ...
Report Number
Forest Health statistics and issues, 2007
Insects and resilience presentation
Young pine and mountain pine beetle - update
2007 update on MPB in young pine
Desperate bark beetles
Young pine time-lapse photos
Executive summary
RSI aerial overview surveys 2007

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