Bulkley Valley Research Centre - Science in the Public Interest

Improving Juvenile Tree Growth Prediction for Complex Mountain Pine Beetle Damaged Stands

Project Reference Number: 2005-07

Project Status: Complete

Led by: Dave Coates, PhD, Research Silviculturist, Ministry of Forests and Range, Smithers

Erin Hall, Assistant Research Silviculturist, Ministry of Forests and Range, Smithers; Jacqueline Prior, Smithers; Rasmus Astrup, Bulkley Valley Research Centre, Smithers

Funder: Forest Investment Account - Forest Science Program

There are major stewardship and long run sustainability concerns in the Mountain Pine Beetle (MPB) damaged stands and landscapes of northern BC. Forest managers require robust, unbiased predictive equations of juvenile tree growth under a range of management conditions in MPB damaged stands. This is an especially pressing need in unsalvaged areas and in managed stands where complex structure remains after salvage. For MPB damaged areas, we will develop and test new juvenile tree growth equations that build upon previous detailed research in northern BC forests (Wright et al. 1998; Coates and Burton 1999; Wright et al. 2000; Astrup, FSP Project Y051256). The improved growth functions will allow models to more accurately predict tree growth and survival across the broad range of management scenarios being practised today in MPB damaged areas. This work is key to the development of SORTIE as one of the models available to assist with the Timber Supply Review in MPB damaged areas.

Predicting the effects of management on long-term forest dynamics involves a complex suite of factors, especially when cutting systems are employed that retain variable levels of canopy trees in time and space. Understory light availability is a good proxy for predicting juvenile tree growth in complex structured northern latitude forests and is certainly the factor most directly manipulated by forest management actions (see references in Coates et al. 2003). Understanding the response of individual juvenile trees to variation in light is therefore fundamental to predicting future growth under a range of management options.


The objectives of this project are to:

1. Undertake field sampling of very small seedlings for the major tree species in two sub-boreal spruce subzones (SBSdk and SBSmc2) and combine this dataset with existing data. We will then examine alternate models in which growth of understory seedlings and saplings is a function of (i) tree species, (ii) tree size and (iii) growing season ambient light availability.

2. Incorporate the new juvenile equations in SORTIE and test juvenile tree predictions against known juvenile growth datasets.

Related Reports

Publication Date Report Title Authors
May 2006 Allometric Relationships of Seedlings and Saplings of Sub Boreal Spruce Tree Species - Extension Note #4 K. David Coates, Erin Hall and Rasmus Astrup
May 2006 Improving Prediction of Juvenile Tree Growth in Mountain Pine Beetle Damaged Stands - Extension Note #3 K. David Coates, Erin C. Hall and Rasmus Astrup