Too late for half-measures to save the environment | Sheila Leslie

Benjamin Spillman | Reno Gazette-Journal

California’s increasingly severe wildfires could be permanently destroying vast amounts of lichens — fuzzy, leaflike organisms that grow on trees and rocks.

It might not sound like much of a problem for people. But it could be bad news for forest ecosystems. Wildlife such as as deer and elk sometimes eat lichen, especially during winter.

It’s also a potential problem for the already threatened northern spotted owl, a raptor that dines on flying squirrels that rely on lichen for survival.

The problem was the subject of a recent study that looked at burn areas in California’s Sierra Nevada and Warner ranges, an area that roughly stretches from Yosemite National Park, north through the Lake Tahoe area and continues to northeast corner of the state.

It found that in areas subjected to severe fire damage, flames destroyed lichen already growing and changed the habitat in ways that could prevent the organism from returning.

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“If we start losing lichen from large areas, it suggests forests could change in pretty substantial ways,” said researcher Jesse Miller, a postdoctoral scholar in the department of environmental science and policy at University of California Davis.

Miller looked at five burn areas, some as many as 16 years post-fire.

In Yosemite, they included areas burned by the Rim and Grouse fires in 2013 and 2009. In the Tahoe area they included areas burned by the Long and Showers fires in 2009 and 2002. And in the Warner Mountains, he looked at the burn area of the 2001 Blue Fire.

“Even the oldest one, 16 years after a fire, there has been very little recovery,” Miller said.

Miller’s study looked at 15 species of lichen, an organism that’s mostly fungus with small amounts of algae.

Jesse ED Miller/Contributed photo

“It has been described as fungi that discovered agriculture,” Miller said.

Miller said lichen survived or returned to portions of burn areas where fire was less severe.

But in places where fires were intense the burning made the landscape unsuitable for lichen to return, Miller said.

That’s because the microclimates that formed after severe burns became too hot and dry for lichen to survive.

Human-induced global warming, caused by the widespread burning of fossil fuels for energy, is making the problem worse.

Warming is making California’s fire seasons longer and hotter, and drier conditions are making fires more intense, which contributes to fires that destroy even large trees that provide shade and habitat for lichen.

Climate change also means that after fires, in addition to the lack of shade, the overall climate in which the lichen once thrived can be too hot and dry to support its return.

According to the study, dry, low-elevation forests such as some of those sampled in the research might be where lichen is most threatened by climate change.

“If the species could keep pace with the rate of climate change, the effects of fire might not be so bad,” Miller said. “But the concern is they might not. These fires happen so quickly and in such a large area, they could cause species ranges to contract faster than they are expanding.”

Miller said forest managers could reduce lichen losses by restoring forests to a healthier ecologic balance.

Jesse ED Miller/Contributed photo

That would mean thinning fuels that contribute to intense fires while retaining large trees that create the forest canopy and support ecosystems.

“Our study suggests lichen can survive those kinds of thinning treatments just fine, the same for prescribed fire,” Miller said.

“In the long run these kinds of treatments prevent these catastrophic, high severity fires.”

Commercial logging, on the other hand, would likely cause more harm than good, he said.

That’s because logging projects tend to take the most economically valuable trees, which are also the most valuable for the ecosystem.

“Commercial logging typically removes the biggest trees, those are the most fire-resistant trees,” Miller said. “The history of commercial logging is actually a major cause the situation we are in.”