Mass tree die-offs remind us of the drought, climate change’s consequences

Trees killed by drought and beetles pose fire risk, but may also be home to wildlife

More than 66 million trees in California have died since 2010 due to the drought and pine beetle infestations, according to a press release from the California Department of Forestry and Fire Protection this week. The accumulation of dead trees is exacerbating wildfires in the southern part of the state, in addition to demonstrating poor forest health.

“From Southern California to the Bay Area to the Sierra, this is happening across the entire state,” said Sandy DeSimone, Director of Research and Education at the Audubon California Starr Ranch Sanctuary. “It’s a really mindboggling problem and everyone is talking about it.”

For scale, there were only 3.3 million dead trees in California from 2010 to 2014. In 2015, officials were worried when that number jumped to 29 million dead trees. In response, Governor Jerry Brown created the Tree Mortality Task Force, a coalition of over 80 stakeholders and government agencies from the local to federal level.

The impacts of this trend are multifold and interwoven. First, the dead trees make excellent tinder for forest fires, as they are dried out from the drought. Healthy forests contain moisture that contains fires; dry forests allow the fire to sustain and spread. Some of the consequences of such prolonged “megafires” are obvious, such as destruction of wildlife habitat and potential damage to homes and building.

There is also a cyclical irony among the dying trees, fires and climate change. As the trees die, they no longer absorb carbon dioxide from the atmosphere. As the trees burn, they release more carbon into the air. In fact, a Berkeley study last year found that forest fires are responsible for somewhere between 5 to 7 percent of California’s total carbon emissions.

Climate change caused by such greenhouse gases has in turn been linked back to drought and beetle epidemics, the causes of the tree die-offs. Climate change can cause precipitation changes, and higher temperatures have increased the range where pine beetles can thrive, spelling trouble for the trees. We also know that climate change threatens 170 bird species in California.

To address the immediate problem of the fires, the focus of CAL FIRE has first turned to removing dead trees to prevent the spread of flames. However, the dead trees—also called snags—can provide home for birds and other small wildlife as well.

“There’s not an easy way to reconcile habitat and nesting in dead trees with the fire potential,” DeSimone said.

However, she did suggest some general guidelines. When drought-weakened trees sustain diseases or pests, when these trees die they can no longer serve as home to birds anyway and should be removed. Additionally, human safety can be a concern to consider.

“At this point, it’s a potential human and ecological disaster,” warned DeSimone.

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