Forest Investment Account (FIA) - Forest Science Program
FIA Project Y072003

    Determining susceptibility of young pine stands to the mountain pine beetle, Dendroctonus ponderosae, and manipulating future stands to mitigate losses
Project lead: Maclauchlan, Lorraine
Imprint: B.C. : BC Ministry of Forests and Range, 2007
Subject: Forest Investment Account (FIA), Dendroctonus Ponderosae, British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
The following proposal best fits the Timber Growth and Value Program: 4.1 Stand and forest dynamics following MPB. Sustainable forest management implies a certain resiliency to disturbances, including forest insects and diseases. To achieve resiliency, forest managers require an understanding of relative susceptibility to forest health factors, particularly those affecting young stands. Approximately 79% of the Canadian inventory of lodgepole pine is found in BC. The area of immature forests in BC totals 14.3 mill ha. Given the scope of the mountain pine beetle (MPB) outbreak, and projected rates of harvest, the area of young pine has the potential to expand exponentially over the next decade. Young stands may be planted, or naturally regenerated, and may receive intensive management to maximize yield and site potential. Activities such as spacing, pruning or fertilization represent a significant investment by forest managers. Expenditures should therefore be based upon the best available science to support sustainable forest management, to ensure the health and success of existing and future plantations. The exponential increase in MPB populations throughout BC intensifies the value of young pine stands to the future sustainability of our resource. An estimated 6.5 mill ha mature pine were affected (red attack) in 2004. In 2003 and 2004, MPB attack was first noticed in pine plantations 30 years and younger throughout northern and southern BC. Plantations suffered up to 30% stem mortality each year. MPB successfully colonized some young trees, subsequently adding to surrounding beetle-pressure, whereas in others there was no sign of brood success. Surrounding beetle pressure from mature stands varied among areas. Bark attributes of successfully attacked plantation trees resembled mature bark rather than bark of young trees. Recent drought conditions could also influence vulnerability. Trees in spaced stands reach diameters that are acceptable to MPB and other beetles at an earlier age than trees in naturally regenerated, densely grown stands. Bark and phloem attributes could be factors in the acceptability of young trees to MPB. Existing plantations are likely very different than historic natural stands, which resulted from insect and fire mortality. Susceptibility parameters currently in use have been determined from natural origin stands. Managed plantations could very well possess different indicators of susceptibility. High-value seed orchards are approaching +25 years, and have attributes similar to those of trees in spaced stands. These orchards represent a significant investment and their loss would set the tree improvement effort back many years. Determining the acceptability of seed orchard trees to MPB under the current high population and under lower endemic population pressures would lead to management recommendations for protection against MPB. There are thousands of ha of plantations in BC >25 years and many more approaching this age. Plantations represent future harvests, habitat and forest structure. Normally, these stands would not be considered at risk to MPB; however they are currently under attack. What degree of risk are these young stands exposed to? Is current mortality caused solely by high beetle pressure, or is climatic change also an influencing factor? Do stand and bark characteristics of managed stands increase susceptibility to MPB over naturally regenerated stands? The primary goals of this project are to determine: 1) key attributes of susceptibility in pine plantations; 2) the best methods to manipulate stand and tree conditions to mitigate potential losses from MPB; and, 3) the risk of incipient populations of MPB building in future young pine plantations once this current outbreak has subsided. This project will determine implications of MPB in plantations. Some attributes to be studied and quantified include: the success of MPB in attacked trees; stand density: basal area; bole attributes; and, presence and severity of stress factors (drought, disease). Stand and landscape parameters include: proximity to infested mature stands and level of beetle pressure from these stands; spatial pattern of attacked and unattacked plantations in relation to clearcuts, mature stands, MPB sources and other plantations. We plan to conduct controlled, replicated experiments at Skimikin Seed Orchard and other pine plantations to determine the level of MPB pressure necessary to overwhelm tree defenses. Beetle pressure will be simulated by 'seeding' plots with mass attacked pine logs spaced throughout the plots. Results from this study will provide the basis for a susceptibility rating system for present and future plantations and will enhance existing management strategies in shaping our future forests.
Related projects:  FSP_Y061003


Determining susceptibility of young pine stands to the mountain pine beetle… (1.1Mb)

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Updated August 16, 2010 

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