Oregon’s conifers suffer a record die-off as the climate crisis hits hard

Scientists have discovered a record number of dead fir trees in Oregon, a harbinger of how drought and the climate crisis are ravaging the American West.

A recent aerial survey found that more than a million acres of forest contain trees that have succumbed to stressors exacerbated by a multi-year drought. Images released by the United States Forest Service show Oregon’s lush green expanses dotted with ominous streaks of red.

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“It’s astounding,” said Daniel DePinte, an aerial survey program manager with the Forest Service who led the agency’s Pacific Northwest region aerial survey, noting that this year has seen the highest rate of mortality for fir trees in this area in history. These evergreen conifers are less able to survive drought conditions than other more vigorous trees that line the landscape.

He and his colleagues scanned the slopes from planes multiple times between June and October, detailing the devastation on digital maps. During that time, it became clear that this year was going to be unlike anything he’d seen before. The report is still being finalized, but dead trees have been identified in areas of 1.1 million acres of Oregon forest. Scientists have started nicknaming it “firmageddon.”

“The size of this is huge,” DePinte said. “A lot of people out there think climate change is just impacting ice sheets or some low-level island out there, but it’s actually having an impact right here in our backyard,” he added. “If this drought continues as climate change continues and we continue to ignore what nature is showing us around the world, that doesn’t bode well at all.”

An ongoing drought, coupled with recent extreme heat, has left more vulnerable trees like spruces struggling to adapt. As the cascading effects of the climate crisis unfold, ecosystems are expected to change. The loss of these trees is a sign that forests may already be starting to change.

“It will be a different forest with a different feel and it will happen across the landscape as nature decides,” said DePinte. “Nature is saying there isn’t enough to support the spruce trees, and over time they will be cleared from those areas.”

Scientists had expected to see signs of stress in the forests, but the sudden increase in mortality was alarming. Prior to this year, the largest area of ​​recorded dead trees in Oregon was in 1952, where tree diebacks were identified on approximately 550,000 acres.

“It’s no surprise that this is happening, but seeing such a spike over a year is concerning,” said Christine Buhl, a forest entomologist with the Oregon Department of Forests. The underlying conditions that caused the peak – record temperatures and minimal rainfall – had an exacerbating effect on the forest due to timing, duration and frequency.

“Hot drought is a double whammy for a tree,” he said, explaining that the roots of drought-stressed trees die, making it more difficult for them to recover even when water is available. Prolonged lack of moisture, especially during growing seasons when rainfall was once again heavy, also damages a tree’s vascular tissues which are used by the tree to draw water.

“It’s kind of like you’re trying to suck a milkshake through a straw but there’s a hole in the straw,” Buhl explained.

Rebuilding those essential tissues takes time and also requires resources. When conditions continue for longer periods of time, some trees are unable to cope. Stressed trees are also more susceptible to other aggressors, including insect infestation and disease. “Sometimes you’ll see trees dying years after severe drought stress,” he said she, “because they’ve just been trying to hold on.”

The loss of these trees can change other ecosystems in the forest. The wave of heat and light, once protected by a thick canopy, can raise stream temperatures or make room for invasive species once kept out of the shade. Some species will thrive on change. Bees that nest in the forest floor, Buhl said, benefit from the burst of sunlight that also helps flowering plants bloom. But others will perish.

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The effects aren’t limited to Oregon, and scientists have observed something similar if much less severe, spruce die-offs in Washington state, even though fewer of these types of trees grow there.

Tree deaths also increase other risks, such as fires. “Long periods of drought and extreme heat can make trees weaker and more susceptible to things like insects and disease outbreaks,” said Will Rubin, a spokesman for the Washington Department of Natural Resources. “That dry, dead, overcrowded lumber becomes more susceptible to fueling those fast-moving, heat-intensive fires blanketing the West in smoke.”

As heat waves and drought conditions intensify in the American West, landscape managers are looking for ways to adapt and increase forest resilience, including through proven treatments like prescribed burning that help the earth heal and protect against catastrophic fires.

“We are trying to help return our forests to this historically resilient state while managing and understanding the impacts of these severe weather events as climate science shows they are more likely to happen more often,” Rubin said.

When it comes to dying, researchers are trying to embrace change. Dying spruces cannot be replanted. “We have to get used to it. We won’t see some species in the same places we expected in the past,” Buhl said. He points out that understanding where the climate will be in the decades to come can help them navigate the problems. “If we can prepare and know that there will be a change in the way where things will look,” he said, “we’ll be much better off.”

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