This article was published on: 11/24/21 9:21 AM
Scientists from Oregon State University and University of Nevada, Reno, have recently published findings suggesting that snowpack duration is one of the important factors in post-wildfire recovery of mountain forests. The research covered nearly 260,000 square miles of the Columbia Basin, our main watershed, which includes a variety of fire-prone landscapes, and has experienced almost 900 fires in the past eleven years. It is a critical habitat for nearly 700 species.
Wildfires are known to have many short-term and long-term implications. Among them: unstable stream banks leading to erosion, debris in water, and water quality. Climate change has resulted in lower precipitation and less snow, which in turn lowers the chances for the forest to regrow vegetation in burnt areas.
Andrew C. Wilson of OSU, Anne W. Nolin (UN, formerly OSU) and Kevin D. Bladon (OSU) in their work published in the Journal of Geophysical Research (JGR), analyzed 24 high severity fires in the Pacific Northwest mountainous regions. Summer precipitation was consistently the number one factor positively correlating with the revegetation of the area. Snow cover frequency, duration, and elevation were the next most important factors in the Oregon and Washington Cascades.
There was an apparent strong correlation between winter snow cover and summer vegetation greenness across the 200-meter elevation band in the region. In the Rockies, at moderate elevations in Montana and at the lowest elevation in Idaho, winter snow cover played a crucial role.
Given the increasing frequency and duration of the wildfires in the Pacific Northwest, investigation of the array of factors contributing to the recovery of vegetation is key. ”Post-wildfire revegetation in forested, mountainous landscapes is complex and depends on many factors, including fire severity, pre-fire vegetation, elevation, slope, aspect, rain, and snow accumulation and melt. Little is known about the linkages between these drivers and revegetation across the PNW,“ reads the paper.
“(…) wildfire season length in the western U.S. overall has increased by roughly 25 days in recent decades, including a massive increase in the Northwest from the mid-1970s, when it was 23 days, to 116 days in the early 2000s,” pointed out Bladon. “That’s attributable mainly to warmer temperatures and drier conditions in the spring and summer.”
With the current trend of wildfires and shorter winters, the forest may not be able to recover to the pre-fire condition.
“That’s at the heart of the challenge of reconciling a changing climate’s ecological forces with postfire forest management goals – the goals are often oriented toward re-establishing forests as they existed before the fire,” Bladon said. “But with shifting climate trends in the region, that might not be the most adaptive path forward for forested landscapes.”
The Farmers’ Almanac forecasts a very typical upcoming winter in our region.
By: Joanna Rosińska