The US Forest Service estimates that California’s multi-year drought has killed off at least 12 million trees over the past year according to the Los Angeles Times. Sources: The Los Angeles Times, Science Signalling
Last month, researchers used aerial surveys to assess the damage created by the parched conditions on more than 3 million hectares of the state’s forests in southern California and in parts of the southern Sierra Nevada.
Millions more trees are expected to perish over the dry, summer months potentially fueling future wildfires but there isn’t much that can be done to prevent the loss, officials say.
Rangers in the San Bernardino National Forest call them “red trees.” Instead of the typical deep green color, large swaths of pine trees now don hues of death, their dehydrated needles turning brown and burnt-red because of the state’s worsening drought.
“Unlike back East, where you have fall colors, here it’s because the trees are dying,” said John Miller, a spokesman for the San Bernardino National Forest.
Years of extremely dry conditions are taking a heavy toll on forestland across California and heightening the fire risk as summer approaches.
“The situation is incendiary,” William Patzert, a climatologist for the Jet Propulsion Laboratory said.
A new study by the US Forest Service tried to assess the scope of the problem.
Researchers estimated that the drought has killed off at least 12.5 million trees in California’s national forests during the drought. The scientists expect the die-off to continue.
“It is almost certain that millions more trees will die over the course of the upcoming summer as the drought situation continues and becomes ever more long term,” said biologist Jeffrey Moore, acting regional aerial survey program manager for the US Forest Service.
Mr Moore and other researchers conducted an aerial survey of more than 8.2 million acres of forest last month.
Using a digital aerial sketch-mapping system, researchers flew in a fixed-wing aircraft about 1000 feet above ground level and surveyed areas in the Cleveland, San Bernardino, Angeles and Los Padres national forests.
Some private lands and Pinnacles National Park in Central California were also surveyed.
Researchers also examined the Tehachapi range, Stanislaus, Sierra and Sequoia national forests, as well as Yosemite and Sequoia-Kings national parks.
Researchers found 999,000 acres of dead trees, Mr Moore said.
In the Stanislaus areas, tree deaths have doubled since July.
“It’s pretty rough,” said Mr Moore, adding that a statewide survey is planned later this year.
“It is cause for concern — but there is not too much to do about it.”
The scarcity of water is not the trees’ only enemy amid the drought.
Weakened and dehydrated, many of the trees are being finished off by bark beetles — tiny brown insects that thrive in dry conditions, chewing away at pines and making them brittle.
Mr Moore said the last time researchers saw so many trees dying was during the great drought of the 1970s. At that time, the National Park Service did not conduct aerial surveys in California, only ground reports, he said.
An estimated 14 million trees or more died between 1975 and 1979. If the drought continues, the number of tree deaths could surpass that era, he said.
