It was the combination of the high temperatures in the afternoon with the sun boring down. We think a lot of those leaves just cooked in place. Chris Still, College of Forestry, Oregon State University
NBC News is the first mainstream news outlet to report on a staggering study that reveals a mass mortality event of fir trees in Oregon and Washington State. Columbia Insight's exclusive investigative news site focuses on environmental news in the Pacific Northwest.
Nathan Gilles of Columbia Insight broke the news that the recent droughts plaguing the PNW have resulted in the death of trees in a jaw-dropping 1900 square miles of forest. He notes that Oregon was the hardest hit by the deaths of fir trees in what researchers at the United States Forest Service refer to as "Firmageddon." The research has yet to be published by the USFS, and the emphasis is put on preliminary.
In an interview with Columbia Insight, DePinte says although his team’s results are preliminary and further analysis is needed, the 2022 Firmageddon appears to be due to a combination of drought coupled with insects and fungal diseases working together to weaken and kill trees.
Extreme heat, including last year’s record-breaking “heat dome,” is also being investigated as a possible cause.
“When a drought event comes around it basically weakens the entire forest to a point where the insects and the diseases start to work in tandem and this pushes a tree over the edge and it succumbs to mortality,” says DePinte.
What’s noteworthy about Firmageddon isn’t just the total area impacted. It’s the number of dead trees within that space.
In some areas as much as 50% or more of fir trees are estimated to have died.
These “severe” die-off’s occurred in central Oregon in forests running from the Oregon/California border northward, according to survey data.
Evan Bush from NBC news writes on a longstanding healthy ecosystem where forests evolved and coexisted with pests such as caterpillars, bark beetles, and root disease. Climate change has disrupted the balance.
Healthy trees typically can defend themselves against these threats. When beetles drill into a tree’s bark, for example, a healthy tree can push the beetles out by excreting pitch, a gooey substance, where they entered the tree, Kohler said.
But disturbances like drought, wildfire and windstorms can stress trees and weaken their defenses. Large numbers of dead and dying trees could allow bark beetles to lay eggs, feed their larvae and flourish.
Scientists still only have a coarse understanding of the factors that are causing widespread die-offs in Oregon, but many view drought as the underlying culprit.
“There are multiple factors at play here. One of the things most of us agree on: The primary factor we have going on here is hot drought,” Buhl said, meaning that the state has been hampered by higher-than-normal temperatures and also low precipitation.
The new normal of scorching heat and drought is a lethal combination weakening trees' ability to survive soil disruption and changing rainfall patterns. The real possibility is that with this much tinder now available, devastating wildfires in 2023 summer are likely.
The deaths by drought are roughly the same area as the trees killed by wildfire. In 2021 scorching heat killed a record number of trees. South-facing slopes had the most deaths; it has now been two years in a row of record-breaking tree mortality in the PNW.