Excerpt from a Greenwire article. I haven’t read the study yet….
Study shows worsening drought threats to Western forests
GREENWIRE | Drought — not wildfires or logging — may be the biggest long-term threat to forests in part of the West, according to researchers from the Forest Service and two universities.
A research paper suggested drought is the main contributor to ongoing losses of dense conifer forests in the southern Sierra Nevada, speeding the conversion of land to nonforest or lower density woodlands. Drought and the beetle infestations it invites were more responsible than the combined effects of wildfire or forest-thinning, researchers said.
In the area the scientists studied, they found that about 213,000 hectares — or slightly more than half of the area that transitioned to nonforest — could be blamed on drought alone. Forty-five percent could be attributed to drought and wildfire combined, and 4 percent to when drought and mechanical activities like thinning coincided.
That and other findings, the researchers said, together point to a need to manage forests through a mix of prescribed fire, thinning in some areas that have grown thick for lack of natural fire, and leaving big trees in place to protect against wildfire and maintain wildlife habitat. It also illustrates the dire future that may await forests in dry regions as the climate warms and wildfires potentially increase.