Wildfire

Norse Peak Fire
Look around and at the ridges to the northeast. These burned trees are remnants from the 2017 Norse Peak Fire. The fire forced the evacuation of Crystal Mountain and threatened the resort. How healthy does this burn look to you? In fact, some fire is a healthy and necessary part of our forest ecosystems. Fires cause disturbance, opening space in the canopy for new growth. Fires do not burn the whole forest evenly, creating a patchwork of habitat that allows many species to thrive. Some plants even require fire to reproduce.

GLOBAL WARMING AND FIRE
Here on the west side of the Cascade Mountains the main barrier to fires is fuel moisture. Our long wet winters and relatively cool summers keep the forest damp and make it harder for fires to ignite. However, as the climate changes Crystal gets less snow in winter with hotter, drier summers and more frequent droughts. That means the forests around Crystal Mountain dry out earlier in the summer. As a result fire season lasts longer, and the fires are more frequent and larger. In 2012 wildfire smoke killed an estimated 245 people in Washington, and sent nearly 2000 people to the emergency room. The total health costs of Washington’s 2012 wildfires surpassed $2 billion. Thanks to increased greenhouse gas emissions and the related increases in temperature and aridity, we can expect larger and more frequent fires in Washington.

FIRE REGIME
When talking about fire, scientists classify forests by their “fire regime.” This takes into account how frequently an area burns and the intensity of those fires. Wetter forests like this one on the west side of the Cascades have fewer fires. In fact, in the wet forests in Mt. Rainier National Park 400 years or more usually pass between fires. When fires do happen they are often “stand replacing” fires like this one, which means intense fires that kill all the trees in an area. In the drier forests east of the Cascades, fire frequency can be as common as every five to twenty years. These fires often have a low intensity, burning away underbrush and saplings but leaving mature fire resistant trees such as ponderosa pine largely unscathed. In these ecosystems, fire suppression dramatically impacts forest health. What do you see? What differences do you notice between burned and unburned areas on this trail? Take a look at which plants and animals you see in each area, and how temperature and moisture differ.

SOURCES
Halofsky, J. S., D. C. Donato, J. F. Franklin, J. E. Halofsky, D. L. Peterson, and B. J. Harvey. 2018. “The nature of the beast: examining climate adaptation options in forests with stand-replacing fire regimes.” Ecosphere 9(3)e02140. March 2018. 10.1002/ecs2.2140 Hemstrom, Miles A, and Jerry F. Franklin.”’Fire and other disturbances of the forests in Mount Rainier National Park.” Quaternary Reserach 18 (1). July 1982. pp 32-51. 10.1016/0033- 5894(82)90020-5 Perry, David A., Paul F. Hessburg, Carl N. Skinner, Thomas A. Spies, Scott L. Stephens, Alan Henry Taylor, Jerry F. Franklin, Brenda McComb, Greg Riegel. “The ecology of mixed severity fire regimes in Washington, Oregon, and Northern California.” Forest Ecology and Management 262 (5). September 2011. pp. 703–717. 10.1016/j.foreco.2011.05.004 Limaye, V. S., Max, W., Constible, J., & Knowlton, K. ( 2019). Estimating the health‐related costs of 10 climate‐sensitive U.S. events during 2012. GeoHealth, 3. https://doi. Org/10.1029/2019GH000202