Forest fire ecology in the Pacific Northwest

 

Different forests and different fire regimes on the east-v west side of the Cascades. (L) One year post-fire in the 2017 Norse Peak Fire, near Mount Rainier National Park. (R) Ponderosa pine and Douglas-fir in the east cascades near Cashmere, WA.

Fire is a natural and integral disturbance that shapes forests in the Pacific Northwest, though the role that fire plays is substantially different depending on geography. For example, many dry forests on the east side of the cascades were historically characterized by frequent fire and were dominated by thick bark fire “resisting” trees such as ponderosa pine – yet are now at risk of high-severity fire from decades of fire exclusion and fuel buildup. Conversely, wet forests on the west side of the cascades were historically characterized by infrequent but very severe fire and were dominated by very-high biomass forests born of past fires. As the climate warms and fire activity increases , ecological outcomes and forest management strategies with regards to fire will vary substantially across the east vs. west side of the cascades. We are capitalizing on recent wildfires that burned across a range of forest conditions and past disturbances to better understand forest fire ecology and management options in the Pacific Northwest. On the east side, we are studying dry forests where fuels treatments were implemented 15 years ago and that later burned in the 2012 Wenatchee Complex fire (Mission Creek Fire and Fire Surrogates site). On the west side, we are studying the 2017 Norse Peak Fire, which burned through a range of pre-fire stand ages (~50 years to ~500 years) in western hemlock / silver fir / Douglas-fir forests. Collectively, we are asking the following questions:

1) How do fuels treatments (e.g., mechanical thinning, prescribed burns) affect resistance and resilience to subsequent wildfire in low-elevation dry forests of the East Cascades?

2) How does fire severity and interval since the last fire affect post-fire vegetation response?

3) How do effective strategies for managing fire-prone forests differ between the east side and west side of the cascades?

 

Funding: USDA National Institute of Food and Agriculture McIntire-Stennis Program & USFS Geospatial Technology and Applications Center (GTAC)

Collaborators: Daniel C. Donato (WA DNR); Joshua Halofsky (WA DNR); Derek Churchill (WA DNR)Jerry F. Franklin (UW-SEFS); Jon Bakker (UW-SEFS); Ernesto Alvarado (UW-SEFS)