Modeling Tree Mortality Following Wildfire in the Southeastern Canadian Mixed-Wood Boreal Forest

Abstract

Abstract We modeled tree mortality three months after a wildfire in the mixed-wood boreal forest (Quebec, Canada) using data from 1963 trees in 36 stands burned under a wide range of fire behavior conditions during the 1997 Val Paradis fire. Stand composition influenced the char height: height of burn was lower in deciduous stands than mixed or coniferous stands. Analysis of species mortality rates revealed that Populus tremuloides Michx. was the least fire-resistant species, whereas Picea mariana Moench and Pinus banksiana Lamb. were the most resistant species. Efficient interactions for conifers exist between crown and cambial resistance to injury and fire behavior, as diameter at breast height (DBH), total tree height (TOTH), and mean bark thickness are characteristic variables throughout the fire behavior range. The best logistic regressions, relating probability of wildfire-induced mortality to morphology and fire variables, always entered char height (CH) at the first step of the stepwise procedure, followed by a morphological variable (DBH or TOTH). The Kappa coefficient used for model validations revealed that logistic regressions using morphologic and fire variables were very efficient as compared to logistic regressions based only on morphologic variables. Potential applications of these results by land managers are discussed. FOR. SCI. 49(4):566–576.