Snag Dynamics Studies

Disturbance events such as major insect or disease outbreaks or wildfires can result in high canopy tree mortality rates, creating many snags that can remain standing for decades. Little attention has be given to how snags affect understory light dynamics. We are undertaking research to develop a snag dynamics behaviour for inclusion in the SORTIE-ND simulation model, specific to the mountain pine beetle disturbed forests of northern British Columbia. We are also working to quantify crown openness of all snag species in the sub-boreal spruce forests and with collaborators for the major snag species of the southern boreal forests of Québec where spruce budworm events are common.  

Implications of Alternate Silvicultural Strategies in Mountain Pine Beetle Damaged Stands
Coates, K. David, Erin Hall. 2005.

This report is one of our first attempts to test model performance in sub-boreal forests damaged by the mountain pine beetle (MPB). We also describe our early work to incorporate a robust snag dynamics behaviour into the SORTIE-ND model. This Technical Report is also summarized in an Extension Note. We use the model to simulate future individual tree and stand growth after different silviculture strategies in MPB attacked stands. We selected four stand types to represent MPB susceptible stands: Pine Minor Spruce, Mixed Pine-Spruce, Spruce Minor Pine, and Pine Dominant. Results of model simulations of understory light environments, natural regeneration survival, and effects of underplanting and delaying planting are reported. For comparision, we present TASS (Tree and Stand Simulator) model projections for single species, even-aged plantations.


Crown openness, light transmission and snag dynamics in boreal forests
Coates, K. David, Julie Poulin, Christian Messier and Paula Bartemucci. .

A paper on snag dynamics in boreal forests is in the review process. It presents results from northern BC and Quebec using methods for snags similar to those described for live trees in Canham et al. 1999.