Contact: Mahadev Sharma and Michael Ter-Mikaelian
How productive is a given forest site? The answer to this question is important for forestry professionals, whether they are writing a silvicultural plan for the site or calculating how much timber it will produce. These professionals use a mathematical model called site index to estimate site productivity. Site index generally reflects how good the site is for tree growth and is defined as average height of dominant and codominant trees at some reference age, usually 50 years.
Traditionally, these indices were based only loosely on site type and on the assumption that the climate is stable. Since both site and climate affect tree growth, researchers are developing dynamic site index equations that account for the effects of climate and site by linking annual stem growth of major species with key climate variables and Ontario’s land classification system.
They are starting with new models for jack pine and black spruce, but they plan to expand their efforts to include white spruce and red and white pine. The improved site index models will provide more effective tools for understanding site productivity, determining how best to manage forest sites, and predicting future forest growth and yield. This work will benefit other modelling efforts as well; for example, they could be used to produce inputs for more complex models, such as Ontario’s carbon budget model (FORCARB-ON).
