Collaborators: Van R. Kane, Bryce N. Bartl-Geller, Nicholas A. Povak, Derek J. Churchill, Paul F. Hessburg, James A. Lutz, Jonathan Kane, Andrew J. Larson

We evaluated the effects of post-fire management on forest structure in mixed-conifer forests of northeastern Washington, USA. We assessed forest structure in areas that had post-fire silvicultural treatments occurring within five years of the fire. Postfire treatments were harvest-only, harvest combined with planting, planting-only, or post-fire prescribed fire occurring within 15 years of the initial fire. We used aerial light detection and ranging (LiDAR) data to measure vertical and horizontal components of post-fire forest structure in treated areas, and in control areas with similar bioclimatic environments and past fire severity as treatments, over a period of 2 to 32 years after fires. We use niche overlap statistics to quantify distributions of individual forest structure components and PERMANOVA to assess forest structural response to the presence or absence of treatments, past fire severity, time since treatment, and bioclimatic setting. Thinning alone or thinning + planting after a fire decreased dominant tree height, vertical complexity, and the relative abundance of single trees. Planting + prescribed fires showed little difference in forest structure relative to untreated controls. Overall, the burn severity of the initial fire was the strongest influence on post-fire structure, and many aspects of vertical and horizontal forest structure showed little difference with increasing time since fire.

This seminar was presented in conjunction with the 2020-2021 Missoula Fire Lab Seminar Series.