Forest Investment Account (FIA) - Forest Science Program
FIA Project Y072148

    Regeneration and Stand Structure following Mountain Pine Beetle infestation in the sub-boreal spruce zone
 
Project lead: Coates, David
Imprint: [BC] :, 2007
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
Description:
Research Priority: Timber Growth and Value Program. Theme 1: Basic Research on tree growth and stand development related to complex stands. Due to the overwhelming magnitude of the Mountain Pine Beetle epidemic, management emphasis has shifted from efforts to control the epidemic to efforts to mitigate itís impact on communities and the environment. The Allowable Annual Cut has been increased in most management units which may lead to a fall-down in timber supply in the medium to long term. It is likely that significant areas of infested forest will never be salvaged due to the large area that is impacted. Forest Managers must now make decisions about which stands should be salvaged, which should be left to regenerate naturally, and which stands may require rehabilitation. Managers are using a variety of modeling tools to assist with these decisions, to predict the long-term consequences of the beetle infestation, and to explore possible management responses to it. These modeling efforts face two barriers: incomplete data on regeneration and stand structure following Mountain Pine Beetle, and models are not available for these ecosystems to predict growth and yield in complex stands: The mountain pine beetle outbreak is leaving residual stand structures consisting of scattered or clumped surviving lodgepole pine trees, interior spruce and subalpine fir of different sizes and ages, and patches of assorted hardwood species. As many of the heavily hit stands (especially the remote ones) will never be salvaged, the future dynamics of these stands and their ability to contribute to the timber supply is largely unknown. There is little or no data on how these complex, unmanaged stands will regenerate. Where forest managers do harvest stands following MPB, they are frequently leaving behind significant amounts of in-stand structure, in order to mitigate the possible environmental impacts of salvage operations, and to mimic the stand structures that would follow a natural disturbance. The regeneration in these complex managed stands is not well understood. Existing forest growth models (eg TASS/TIPSY) were developed for contemporary forest management; largely even-aged stands with little or no in-stand structure; they were not designed to deal with the complex stands that will regenerate after Mountain Pine Beetle. In contrast, SORTIE-BC is specifically designed to simulate the development of irregular multi-species stands (Coates et al. refs.) This project will prepare a comprehensive data set that describe stand structures and regeneration found several years after pine beetle attack, across diverse site types and several biogeoclimatic subzones in the north-central Interior. The data will be collected so that it can be applied in various modeling environments, including further development of SORTIE BC. The thesis work of a UNBC masters student will evaluate the influence of pre-existing site, stand, and landscape conditions on residual stand structure and the prospects for natural stand recovery. This will allow for immediate application of the data to the pressing question of how stands regenerate following MPB. Depending on his/her particular interests and abilities, he/she may explore stand recovery and intervention scenarios using SORTIE-BC, or this work will be done by Coates, Hall and Burton." Research Methods Approximately 300 temporary sample plots will be installed in four biogeoclimatic sub zones of the sub-boreal spruce. Plots will be randomly located in stands within the area affected by MPB. Plots will be located to cover all site series, and to include stands at various ages since being infested by MPB. Because the study area includes some stands that were infested seven to eight years ago, the study will sample stands from zero to eight years following infestation. This will ensure that the early response of stands following disturbance can be assessed. Natural Regeneration: Observed patterns of recruitment are a result of a broad suite of factors: yearly variation in seed production, seed dispersal opportunities, type and distribution of seedbeds and their favourability, microclimate, potential for vegetative reproduction and the abundance of seed or seedling predators. In this study we will quantify tree seedling recruitment across the full range of stand types affected by the MPB. We will pay particular attention to the three most critical factors affecting recruitment success in northern forests: abundance and condition of parent trees, seedbed substrate distribution and seedbed substrate favourability. We will quantify established seedlings - those that have survived at least two full years since germination. We will strive to develop empirical recruitment relationships that can be used in stand level models (e.g., SORTIE, PrognosisBC). Stand Structure: We will establish fixed radius plots to quantify stand structure using methods compatible for sharing data with other research groups (see Linkages). In general, this will involve establishment of fixed radius or prism plots to quantify shrub and tree communities.
Related projects:  FSP_Y061148
Contact: Coates, Dave, (250) 847-6386, dave.coates@gov.bc.ca

Updated August 16, 2010 

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