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Stewardship of western larch forests in an era of uncertainty

September, 2015

Looking up at two larches turning yellow in the fall, with a clear blue sky in the background.
Western larch-mixed conifer forests regulate numerous ecosystems goods and services while providing stellar views. Coram Experimental Forest in the fall.
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.


Several trees marked with orange paint.
Flathead National Forest and Coram Experimental Forest sites are marked for treatment. Orange paint on tree stems tells loggers which trees are to be left uncut.
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.

  • The Resistance treatment aims to maintain relatively unchanged structure and composition over time by using commercial thinning from below.
  • The Resilience treatment aims to change current stand structure so a similar structure and composition re-develops in time. This treatment will create 2-4 acre openings with scattered reserve tree clumps in the openings. Planting will supplement natural regeneration with shade-intolerant species.
  • The Transition treatment aims to actively facilitate change toward the most future-adapted composition. This treatment will largely remove the overstory but retain about seven reserve tree clumps per acre as a seed source and for long-lasting structure. Planting will supplement natural regeneration with off-site, species and genotypes that are best suited for future climate.
  • The relative performance of these three treatments over time will help managers identify the values and tradeoffs associated with managing for climate adaptation, whether managing to reduce future impacts on established structure and composition or to facilitate adaptive responses more suited for expected climate and disturbance.


Other forest types and sites in the national ASCC project network include:

  • red pine on the Cutfoot Experimental Forest, Minnesota
  • mixed-conifer on the San Juan National Forest, Colorado
  • longleaf pine/hardwood on the Jones Ecological Research Center, Georgia
  • northern hardwoods on the Second College Grant Forest, New Hampshire


Crotteau, Justin ; Sutherland, Elaine K. ; Jain, Terrie B. ; Wright, David K. ; Jenkins, Melissa ; Keyes, Christopher ; Nagel, Linda M. , 2019
Nagel, Linda M. ; Palik, Brian J. ; Battaglia, Mike A. ; D'Amato, Anthony W. ; Guldin, James M. ; Swanston, Christopher W. ; Janowiak, Maria K. ; Powers, Matthew P. ; Joyce, Linda A. ; Millar, Constance I ; Peterson, David L. ; Ganio, Lisa M. ; Kirschbaum, Chad ; Roske, Molly R. , 2017


Related Events

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.


National ASCC website

Northern Rockies Adaptation Partnership website

Flathead Forest research project seeks to adapt forests to climate change, Missoulian, October 21 2017

Project Contact: 

Principal Investigators:
Melissa M. Jenkins - Flathead National Forest
Linda M. Nagel - Colorado State University

Christopher Keyes - University of Montana

Research Staff:
Courtney Peterson - Colorado State University

Funding Contributors:
Northern Region Regional Inventory and Monitoring Board