Washington, District of Columbia 2021-07-27 12:50:11 –
July 27, 2021
In recent years, wildfires on the west coast have become bigger and more damaging. The combination of nearly a century of fire extinguishing and hotter and drier conditions has prepared the tinderbox to ignite, destroy houses and pollute large areas of air.
A new study, led by the University of Washington and the University of California, Santa Barbara, uses a model focused on forests in eastern California in the Sierra Nevada Mountains to long-term wildfires under temperature rise and drought scenarios. I’m looking into the future. NS studyPublished in the journal Ecosphere on July 26, it was found that there was a burst of wildfire activity over the first approximately 10 years, followed by repeated fires that reduced area.
“That first wildfire explosion is in line with what we are seeing in the west today. Fuel buildups, coupled with increasingly hot and dry conditions, are these very large and catastrophic. It will lead to a great fire event, “said the lead author. Maureen Kennedy, Associate Professor at the University of Washington Tacoma. “But our simulations show that if a fire continues in one area, the fire becomes self-limiting and each subsequent fire can be smaller than the previous one.”
According to Kennedy, how climate change, tree growth and wildfires interact over the next few decades has just begun to be investigated through experiments and simulations. Existing models of vegetation often assume that wildfires occur at set intervals, such as every 10 years, or based on past wildfire risk patterns in the ecosystem. However, these previous patterns may not be the best guide to the future.
“The big question is what happens with climate change. Will the relationship between climate and wildfires over the last three decades continue? Or do you have any feedback? Because these Extreme droughts that continue to burn fuel and limit new growth will eventually run out of fuel for wildfires, “says Kennedy.
A new study used a model that included feedback between climate, vegetation growth, water flow, and wildfire risk to simulate the Big Creek basin outside Fresno, California, near the site in September 2020. Creek fire.. Climate models here suggest that conditions are likely to remain hotter and drier, as in other parts of the west.
The results of the 60-year simulation show that under drought and rising temperatures, large-scale wildfires last for about 10 years, then occur in warm and dry conditions, but then become smaller over time. It shows that. Even in the absence of wildfires, forest trees are less productive and stressful in hot, dry conditions, resulting in a decrease in number and size over time. These findings are likely to apply to other forests experiencing drought, said Kennedy, who is currently using the model in other areas.
What happens in the long run is now important to the plan. According to Kennedy, the current understanding is that communities need to co-exist with wildfires rather than eliminate them altogether. The combination of open burning and thinning has the potential for the future of forest management as it addresses both wildfires and climate change.
“The density of forests is so high that trees draw large amounts of water from the soil,” says Kennedy. “There is increasing evidence that thinning forests can relieve drought stress and create drought-resistant forests, which should also help, for example, reduce the effects of the first pulse of a wildfire. . “
After thinning small trees, managers can do open burning to remove kindling and small materials on the floor. But to know how to manage forests in this way, you need to understand the local weather conditions, plant growth, and how wildfire risks will occur in the coming decades.
“It’s important to include climate change, so we know the range of potential future consequences of change,” Kennedy said. “For example, how often do you need to repeat fuel processing? Is that different under climate change?”
Kennedy was another co-author Recent research It uses the same model to distinguish how climate change and fire extinguishing increase the risk of wildfires in different parts of Idaho.
“Our” new normal “is not static,” he said. Christina (Naomi) Tag, A co-author of both studies and a professor at the University of California, Santa Barbara, who developed the RHESSys-FIRE model used in the study. “Not only is our climate changing, but our vegetation (fuel of fire) responds to changing conditions. Our work is on these fires, forest productivity and growth trajectories. It helps to understand what it looks like. “
This study was funded by the National Science Foundation Network and the US Forest Office. Other co-authors are Ryan Bart at the University of California, Merced and Janet Choice at the University of California, Santa Barbara.
NSF Grants: EAR-1520847, USFS
Possible future for Western wildfires: Decade-long burst, followed by gradual decline Source link Possible future for Western wildfires: Decade-long burst, followed by gradual decline