- A new study found some of the forests in California's Sierra Nevada no longer match their climate.
- About 20% of conifers in the Sierra Nevada are experiencing "vegetation climate mismatch."
Some of the forests in California's Sierra Nevada mountains are at risk of disappearing as the climate they are in can no longer support them, according to a new study.
In a paper published last week in PNAS Nexus, researchers at Stanford University found a fifth of the conifer forests in the mountain range are now stuck in weather that is too warm for them.
The term "zombie forest" is being used to refers to these tree, that are still standing for now but may not be in the future.
"They're cheating death, in a way," Avery Hill, the lead author of the study, said. "As soon as some kind of disturbance event — in California this is probably a wildfire — shakes things up, they won't rise again. They won't keep standing."
When trees or other plants are no longer suited to the environment they are in, it's called a "vegetation climate mismatch." The study estimated that about 20% of conifers in the Sierra Nevada are currently experiencing this and that the number is likely to double in the next 77 years.
While the older trees are still able to survive, younger trees are having a harder time getting established. Other disturbances the forests could face include extreme drought or a logging event. The study found that in the case of a disturbance, the trees are more likely to be replaced by vegetation that is better adapted to a hotter and drier climate.
The conifers of the Sierra Nevada include ponderosa pine, sugar pine, and Douglas fir. They cover some of the country's most beloved landscapes, including the Yosemite Valley, Sequoia National Park, and Lake Tahoe. The trees are also some of the tallest living things on Earth.
"Given the large number of people who live in these ecosystems and the wide range of ecosystem services they confer, we should be looking seriously at options for protecting and enhancing the features that are most important," Chris Field, a co-author of the study said study and the director of the Stanford Woods Institute for the Environment, said in a press release.
The researchers said the maps included in the study could be used to adopt better wildfire management and develop strategies for post-wildfire restoration.
"Our maps force some critical – and difficult – conversations about how to manage impending ecological transitions," Hill said in the release. "These conversations can lead to better outcomes for ecosystems and people."
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