There are warning signs that some forests in the western U.S. may have a hard time recovering from the large and intense wildfires that have become more common as the climate warms.
After studying 14 burned areas across 10 national forests in California, scientists from UC Davis and the U.S. Forest Service said recent fires have killed so many mature, seed-producing trees across such large areas that the forests can’t re-seed themselves. And because of increasingly warm temperatures, burned areas are quickly overgrown by shrubs, which can prevent trees from taking root.
“With high-severity fires, the seed source drops off,” said study co-author Kevin Lynch, a forest researcher at UC Davis. “We aren’t seeing the conditions that are likely to promote natural regeneration.”
Historically, severe fires were uncommon in the forests covered by the study, largely made up of yellow pines and mixed conifers, but extended drought and heatwaves have exacerbated fire conditions across the West. The changing climate is also seen as a factor in recent wildfires in the Southeast, which is also mired in drought.
For the study, published Wednesday in the journal Ecosphere, the researchers surveyed 1,500 plots in burned areas at different elevations in the Sierra Nevadas, Klamath Mountains, and North Coast regions. There was no natural conifer regeneration at all in 43 percent of the plots, they reported.
From InsideClimate News: https://insideclimatenews.org/news/21122016/california-forests-wildfires-climate-change