Royal Oak Tribune

Climate change is hastening the demise of Pacific Northwest forests

- By Nathan Gilles,

Deep inside a forest in Oregon’s Willamette Valley stands a dead “Tree of Life.”

Its foliage, normally soft and green, is tough and brown or missing altogether. Nonetheles­s, the tree’s reddish bark, swooping branches and thick, conical base identify it as the Pacific Northwest’s iconic western red cedar.

Christine Buhl, a forest health specialist for the Oregon Department of Forestry, plunges a tool called an increment borer into the dead tree’s trunk. Twisting the handle of the corkscrew-like borer, Buhl extracts a long, thin sample of the tree’s inner growth rings.

The rings become thinner over time, indicating the tree’s growth slowed before the tree finally died, a sign that this red cedar, like thousands of others in Oregon and Washington, died from drought.

“That’s why it’s the canary,” says Buhl. “Any tree that’s less drought tolerant is going to be the canary in the coal mine. They’re going to start bailing (out).”

For thousands of years, people have used red cedar to make everything from canoes to clothing.

Red cedar’s many uses have earned the species endearing names, including the “Tree of Life.” More recently, scientists have started calling this water-loving relative of redwoods by a less flattering name: “the climate canary.”

Last year, Buhl and colleagues reported that red cedars were dying throughout the tree’s growing range not because of a fungus or insect attack, but due to the region’s “climate change-induced drought.”

Red cedars aren’t alone. In recent years, at least 15 native Pacific Northwest tree species have experience­d growth declines and die-offs, 10 of which have been linked to drought and warming temperatur­es, according to recent studies and reports.

Many researcher­s, Buhl included, are now arguing that these drought-driven die-offs are the beginning of a much larger and long-predicted shift in tree growing ranges due to climate change.

Trees, and plants generally, have growing ranges that are largely determined by climate factors, namely moisture and temperatur­e.

For decades, scientists have argued that as atmospheri­c warming continues, growing ranges in the Northern Hemisphere will shift upslope in elevation and farther north, leaving many trees stranded in a warmer, drier world.

As climate mismatch sets in, trees are expected to dieoff and not grow back, according to prediction­s.

DanielDePi­nte,ForestServ­ice aerial survey program manager, suspects range changes are driving “Firmageddo­n.” A term coined by researcher­s, including DePinte, “Firmageddo­n” refers to the more than 1,875 square-mile (4,856-square-kilometer) dieoff of five fir species in Oregon, Washington and northern California.

“The forests are moving uphill,” said DePinte.

DePinte and colleagues first identified and named the massive, drought-driven fir “mortality event” last year while surveying area forests via airplane.

According to tree-range prediction­s, climate-induced die-offs are expected to start at the edges of growing ranges, including at lower-elevation locations that are predicted to become too warm and dry for many species.

DePinte’s survey revealed that the largest die-offs associated with Firmageddo­n are occurring at lower-elevation sites.

Buhl and colleagues found a similar pattern with western red cedar. Mortality was greatest at sites less than about 650 feet (200 meters) in elevation west of the Cascade Range, according to their analysis.

Scientists have also observed a similar pattern for Douglas fir, the region’s leading commercial timber species. Douglas fir is currently experienci­ng a 720-squaremile (1,865-square-kilometer) die-off, the majority in the Klamath Mountains near the southern Oregon cities of Ashland and Medford.

 ?? AMANDA LOMAN — THE ASSOCIATED PRESS ?? Christine Buhl, a forest health specialist for the Oregon Department of Forestry, uses an increment borer to core a dead western red cedar at Magness Memorial Tree Farm in Sherwood, Ore., on Oct. 11.
AMANDA LOMAN — THE ASSOCIATED PRESS Christine Buhl, a forest health specialist for the Oregon Department of Forestry, uses an increment borer to core a dead western red cedar at Magness Memorial Tree Farm in Sherwood, Ore., on Oct. 11.

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