Forest Investment Account (FIA) - Forest Science Program
FIA Project M085169

    Mountain pine beetle impacts and risk projections in young lodgepole pine stands
 
Project lead: Maclauchlan, Lorraine (BC Ministry of Forests and Range)
Contributing Authors: Maclauchlan, Lorraine E.; Cleary, Michelle R.; Rankin, Leo; Stock, Arthur J.; Buxton, Kevin; Brooks, Julie E.
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
Description:
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 collapse of the outbreak. Brood production in young pine is highly variable with certain tree attributes, physiological parameters, site and climatic variables differing from those found in mature trees and potentially influencing MPB populations. The effects of climate change coupled with intense management of young plantations, has resulted in trees attaining a larger size earlier. This change may allow MPB to build from endemic to incipient to outbreak mode differently than seen in the past. Elucidation of these characteristics and relative brood success rates will provide valuable information for developing susceptibility ratings for future forests. Lab and in situ experiments will isolate conditions important to current and future stand risk. An additional year of targeted aerial and ground assessments, evaluation of permanent plots established throughout impacted ecosystems and treatment regimes, and continued study into the biological and physical attributes influencing brood success and incipient populations in younger age classes will be conducted in 2007-2008. This data is critical to completion, testing and validation of ongoing work and risk model projections. Within the scope of this project, we will determine losses in age 20 to 55 year stands by ecosystem, 5-year age increments, geographic location, outbreak stage, and species composition. The proposed study will utilize collected data as a baseline for further work in rehabilitating highly impacted young stands and determining which remaining residual stands are viable. Sampling will be conducted using existing plots and survey protocol already established, with additional data collection including growth, development, species composition and health of residual stems within highly impacted stands. Industry and government must have the information to maximize and prioritize the harvest of mature stands that pose a risk to adjacent young stands and to ensure prompt regeneration of severely impacted young stands. A current and reliable inventory of mortality in young stands is imperative for sound forest management decisions in timber supply reviews. Not every young pine stand can be physically assessed; therefore an alternate method of estimating risk must be made available. A risk model is the tool needed to direct forest management efforts and investment. In order for this model to be confidently applied across the breadth of the MPB outbreak area, a third year of research support is necessary. Ministry of Forests and Range. 2005. Vegetation Resource Inventory Data base.

    Deliverables:

Executive summary (19Kb)
RSI aerial overview surveys 2007 (3.2Mb)
Forest Health statistics and issues, 2007 (10.0Mb)
Insects and resilience presentation (6.2Mb)
Young pine and mountain pine beetle - update (6.7Mb)
2007 update on MPB in young pine (4.5Mb)
Desperate bark beetles (4.6Mb)
Young pine time-lapse photos (6.0Mb)

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Updated August 16, 2010 

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