By Sonia A. Hall
Pacific Northwesterners, especially those of us living and breathing in the inland Northwest, expect wildfires every summer. It’s not about if, but about when, where, and how severe they will be, both in forest and rangeland landscapes. As with many other aspects of natural resource management, climate change continues to add a layer of complexity and uncertainty both in terms of the patterns of fire expected in the future, and in terms of the response of land managers. The USDA’s Northwest Climate Hub’s April 2020 newsletter highlighted the findings of two scientific articles that are addressing questions around future patterns in wildfires and what can be done to prepare.
The first is an article that synthesizes what climate change means for Northwest wildfires, described in UW News. The researchers looked at a wide array of existing studies—from paleoecological studies, through empirical studies looking at recent climatic variability and change, to forward-looking studies using future climate projections—to synthesize the impacts of climate change on fire frequency, extent and severity. Their published conclusions: “… protracted warmer and drier conditions will drive lower fuel moisture and longer fire seasons in the future, likely increasing the frequency and extent of fires compared to the twentieth century. Interactions between fire and other disturbances, such as drought and insect outbreaks, are likely to be the primary drivers of ecosystem change in a warming climate” (Halofsky et al. 2020). Check out the full, open access article to learn more details.
The second article explores the effectiveness of different thinning and prescribed burning treatments by studying the impacts the Carlton Complex fire had in 2014 in Washington State. One aspect of this study that I really liked was the shift away from searching for a yes/no answer to the question of whether treatments worked. Instead, Prichard and her colleagues (2020) took a more nuanced approach, and discuss what impact different treatments had on what happened during and after the fire, even if the treatments did not result in the fire being stopped cold at their boundary. Check out what Prichard and her colleagues (2020) say about how treatments led to more trees surviving the fire, and learn about the nuances of which treatments made the greatest difference in the article published in Ecological Applications.
As wildfires continue to be a regular part of life in the Northwest, these studies add to the body of knowledge helping land managers understand what to expect, both from fire and the restoration treatments they might implement.
Halofsky, J.E., Peterson, D.L. and Harvey, B.J., 2020. Changing wildfire, changing forests: the effects of climate change on fire regimes and vegetation in the Pacific Northwest, USA. Fire Ecology, 16(1), p.4.
Prichard, S.J., Povak, N.A., Kennedy, M.C. and Peterson, D.W., 2020. Fuel treatment effectiveness in the context of landform, vegetation, and large, wind‐driven wildfires. Ecological Applications, e02104.