Reduced fire severity offers near-term buffer to climate-driven declines in conifer resilience across the western United States

Abstract 

Warmer and drier climate conditions in western U.S. forests are making it less likely that trees can regenerate after wildfires, according to this study published in the Proceedings of the National Academy of Sciences. Specifically, it found that warmer, drier conditions over the past four decades have led to a decline in tree regeneration after wildfires and this trend is expected to accelerate in the future. The most vulnerable forests were in drier regions in the Southwest and California, while forests in the wetter and cooler regions of the northern Rocky Mountains and Pacific Northwest are still expected to support conifer regeneration in the near-term future. Importantly, the research also found that ecologically based forest management can partially offset climate-driven declines in tree regeneration by limiting fire-caused tree death, but only if action is taken quickly. This study provides timely information to optimize new state and federal initiatives to increase the pace of ecologically based forest management across millions of acres of Western forests. The lead authors from The Nature Conservancy, the University of Montana, and the US Forest Service assembled the most extensive data set yet collected in the region collected by more than 50 research teams over 10,000 plots to evaluate regeneration of eight major tree conifer species after 334 wildfires.

Citation

Davis, K.T., Robles, M.D., Kemp, K.B., Higuera, P.E., Chapman, T., Metlen, K.L., Peeler, J.L., Rodman, K.C., Woolley, T., Addington, R.N., Buma, B.J., Cansler, C.A., Case, M.J., Collins, B.M., Coop, J.D., Dobrowski, S.Z., Gill, N.S., Haffey, C., Harris, L.B., Harvey, B.J., Haugo, R.D., Hurteau, M.D., Kulakowski, D., Littlefield, C.E., McCauley, L.A., Povak, N., Shive, K.L., Smith, E., Stevens, J.T., Stevens-Rumann, C.S., Taylor, A.H., Tepley, A.J., Young, D.J.N., Andrus, R.A., Battaglia, M.A., Berkey, J.K., Busby, S.U., Carlson, A.R., Chambers, M.E., Dodson, E.K., Donato, D.C., Downing, W.M., Fornwalt, P.J., Halofsky, J.S., Hoffman, A., Holz, A., Iniguez, J.M., Krawchuk, M.A., Kreider, M.R., Larson, A.J., Meigs, G.W., Roccaforte, J.P., Rother, M.T., Safford, H., Schaedel, M., Sibold, J.S., Singleton, M.P., Turner, M.G., Urza, A.K., Clark-Wolf, K.D., Yocom, L., Fontaine, J.B., Campbell, J.L., 2023. Reduced fire severity offers near-term buffer to climate-driven declines in conifer resilience across the western United States. Proceedings of the National Academy of Sciences 120, e2208120120 https://www.pnas.org/doi/abs/10.1073/pnas.2208120120