Western larch (Larix occidentalis) is a conifer species with deciduous needles, a long life span, and high fire resistance and tolerance that grows in the interior Northwest U.S. and British Columbia. Extensive western larch-mixed conifer forests in the Northern Rockies provide valuable timber, habitat for high risk wildlife, and many other ecosystem benefits. However, 20th century fire exclusion and widespread logging have caused shade-tolerant species to succeed larch, and projected climate-related changes (drought and fire) also pose a serious risk. Land managers need the best available science to manage dense, at-risk stands while mitigating the effects of climate change to perpetuate western larch forests.
The Rocky Mountain Research Station and Flathead National Forest are collaborating in a nation-wide study called Adaptive Silviculture for Climate Change (ASCC). The goal of this project is to test different silvicultural approaches to climate change adaptation that will serve as useful examples across the country.
In developing treatments for western larch forests, the project team considered direct and indirect regional climate predictions: drier summer and wetter winter/spring; earlier snowpack melts; longer fire seasons with more frequent fire; and more frequent insect and disease outbreaks. Four silvicultural treatments were designed to address these climate-driven concerns: no-action Control, Resistance, Resilience, and Transition. These treatments are meant to forestall, allow, or encourage change in forest structure and composition given changing climate and associated disturbances.
The Northern Rockies’ ASCC project is a long-term study. Because climate changes slowly and trees take long to develop, this study may not realize gains until years in the future. However, responsible stewardship of western larch forests includes preparing for them for the future, even if it takes time.
Four replicates of each treatment are marked for harvest and will be cut in 2019-2020, while planting will take place in 2022. Pre-treatment monitoring (vegetation and fuels) has been completed before harvest. Subsequent monitoring will track forest responses to treatment.
Other forest types and sites in the national ASCC project network include:
Crotteau, J.S., E.K. Sutherland, T.B. Jain, M.M. Jenkins, D.K. Wright, and C.R. Keyes. Montana Adaptive Silviculture for Climate Change: Coram Experimental Forest/Flathead National Forest. Oral presentation. 12th North American Forest Ecology Workshop. June 27, 2019.
Crotteau, J.S., E.K. Sutherland, T.B. Jain, M.M. Jenkins, D.K. Wright, C.R. Keyes, L.M. Nagel, and C. Peterson. A forest management framework for climate adaptation. Oral presentation. Juneau, AK Society of American Foresters chapter meeting. Juneau, AK. March 14, 2019.
Crotteau, J.S., E.K. Sutherland, T.B. Jain, M. Jenkins, D.K. Wright, and A. Rollwage. Stewarding western larch in the Northern Rockies with the Adaptive Silviculture for Climate Change Project. Poster presentation. Montana Society of American Foresters Annual Meeting. Whitefish, MT. April 13, 2018.
Sutherland, E.K., Bollenbacher, B., Jain, T., Jenkins, M., Nagel, L., Roske, M. Adaptive Silviculture for Climate Change in the Northern Rockies. Poster presentation. 2017 National Silviculture Workshop, Flagstaff, AZ. 18-20 July 2017.