Postfire Growth of Pseudotsuga menziesii and Pinus contorta in the Northern Rocky Mountains, USA

Dendroecological methods were used to study the effects of wildfire on radial growth of Pseudotsuga mniiesii (Douglas-fir) and Pinus contorta (lodgepole pine) in the northern Rocky Mountains. Mean basal area increment during a 4-year postfire period declined relative to prefire growth in 75% of burned P. menziesii trees and 70% of P. contorta trees. Percent of crown volume scorched was the most important variable related to postfire growth of P. menziesii, while basal scorch was slightly more important than crown scorch to postfire growth of P. contorta. Postfire growth always declined when crown scorch exceeded 50% in P. menziesii and 30% in P. contorta. None of the significant regression models had high predictive capability because of the large amount of variance in the data. It is clear, however, that crown injury is critical to postfire survival and growth of P. menziesii, while basal injury is critical for the thin-barked species P. contorta.