Forest Investment Account (FIA) - Forest Science Program
FIA Project M086009

    Identification of young pine stands at high risk to mountain pine beetle through an integration of GIS analysis and field evaluation techniques
 
Project lead: Maclauchlan, Lorraine (BC Ministry of Forests and Range)
Contributing Authors: Maclauchlan, Lorraine E.; Hodge, Janice
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
Description:
Of the 14.9 million ha of pine in BC of various ages, there are approximately 1.96 million ha of young pine (natural regeneration and managed plantations) in between the ages of 20-55 years. Over 1.1 million ha of these are over 80% pine. Within this inventory of young pine, over 1 million ha is between ages 20-35 years (MOFR 2005). These stands represent future harvests, habitat and forest structure. Many of these young stands are currently being impacted by the mountain pine beetle (MPB) and associated bark beetles (e.g. Ips pini). The risk to our future forest inventory from MPB is a major concern of forest industry and government alike. Assessments conducted in 2006 (Maclauchlan 2005, FSP Y072003) show that 75% of young stands in the core outbreak area had some level of MPB attack. Stands over 40 years of age that are spaced, or pruned, are generally not discriminated from mature stands by the MPB and are being attacked at the same frequency and intensity as adjacent mature stands (Maclauchlan 2005). Attack levels in stands surveyed in 2006 ranged from <1% to >95%. This level of attack renders the stand NSR (non-satisfactorily restocked) and therefore must be scheduled for reforestation. Forest for Tomorrow (FFT) has initiated extensive reforestation plans for fire-killed and MPB-killed stands (primarily mature) but has not yet accounted for the potential mortality in young stands. In these stands, as little as 25% mortality could cause a stand to be classified as NSR. Given the MPB pressure and levels of attack observed from 2004-2006, this could occur over 2-3 years. As with mature stand risk (Safranyik et al. 2004; Shore and Safranyik 1992; Safranyik and Linton 1985; Safranyik and Jahren 1970) risk to young stands is highly dependent upon the status of adjacent stands or land. This status has been quantified in terms of beetle risk to the young stand (low-high levels of attack), temporal risk (e.g. whether the MPB population in the adjacent stand is low, static or declining) and if the young stand is adjacent to cutblocks, or other bare land (low risk) (Shore and Safranyik 1992; McGregor et al. 1981). Other trends that are becoming evident is the classic “oldest and largest” first rule with the MPB, although the largest trees are not always the oldest in young treated stands. The geographic location is also a key factor. Fewer young stands have as yet been impacted by the MPB in the southern portion of the SIR (Southern Interior Region, e.g. south of Kamloops). The highest mortality to date is in the “core outbreak area (Prince George, Vanderhoof, Quesnel and Central Cariboo Districts). It is imperative that forest managers, and those directing the FFT program, have the necessary tools and information to maximize both the immediate harvest of mature stands posing a threat to young pine as well as placing high priority on reforestation of impacted stands. The entire 2 million ha of young pine cannot be assessed on the ground; therefore an alternate method of estimating potential risk must be elucidated. With data collected to date, targeted GIS analysis of past years MPB attack, and fieldwork to test the results of the “young stand risk rating”, some guidelines could be provided to managers in a timely manner. This combined GIS/field verified approach to estimating risk would provide necessary guidelines using reasonable stand-level measurements. The objective of this project is to provide a tool that will prioritize young pine stands with the highest risk to MPB attack. This will enable forester to prioritize stands for surveys, treatments or rehabilitation thus mitigating or reducing impact. The long-term objectives are to quantify risk (probability of attack) from adjacent mature stands; and to quantify within stand parameters to estimate the ultimate impact of MPB attack. Young stand susceptibility will be based upon stand age, density, tree size and basal area, and origin of the young stand (e.g. harvested, fire-origin, planted, natural). The risk to young stands will be based upon current and past levels of MPB attack and availability of mature hosts. Potential management options will be developed, including accelerated harvest of adjacent mature stands, fertilization and others to minimize or mitigate further losses in young stands. The objectives are to: i) determine the number of years, and intensity (trace, light, moderate, severe, very severe), of MPB activity in adjacent mature stands, by conducting a GIS overlay analysis using the Provincial Aerial Overview MPB mapping and MOF Inventory database; ii) quantify adjacency parameters for young stands such as level of harvest, stage of outbreak (as determined in (i)) and geographic area (core MPB outbreak area versus new outbreak areas in south) to determine the stage at which risk to young stands increases or diminishes significantly; iii) field verify those assumptions identified in (i) and (ii); and, to determine through GIS analysis, modeling and field sampling, the level of risk to young pine stands adjacent to mixed species stands impacted by MPB. The 2008 objectives are to: i) field validate risk projections formulated in 2006/2007; ii) determine key model parameters and conduct the risk analysis using these modified parameters. The final stage of the project will be to again validate the model with field data collected in 2007.
Contact: Maclauchlan, Lorraine, (250) 828-4179, Lorraine.maclauchlan@gov.bc.ca

    Deliverables:

Executive Summary (13Kb)

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Updated August 16, 2010 

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