2021 heat dome left Rhode Island-sized damage in Oregon and Washington forests

Using satellite imagery, researchers have discovered that nearly 5% of Oregon and Washington’s western forest canopy — about the size of Rhode Island — was scorched and damaged in the multi-day 2021 heat dome.

The wave of extreme heat across the Northwest from June 25 to 29, 2021, brought the temperature in Portland to 116 degrees, killing 70 people in Multnomah County alone.

It also took a toll on the region’s forests, turning tree canopies from green to red, orange and brown within hours. That’s a sign that the leaves were scorched, healthy leaf tissue died and chlorophyll production — a pigment that gives plants their green color and helps them absorb sunlight — stopped, researchers from Oregon State University and the U.S. Forest Service found.

Their study, published Oct. 30 in the journal Global Change Biology, described it as an “unprecedented amount of foliage death.” As leaves die, trees experience acute stress that leads to slow growth, declining immunity to pests and fungus and in some cases accelerated death.

https://washingtonstatestandard.com/2025/11/13/repub/2021-heat-dome-left-rhode-island-sized-damage-in-oregons-washingtons-western-forests/