California drought endangers millions of trees

As many as 58 million large California trees are facing severe danger because of the drought, according to a new scientific study.

The study, released Monday by the Carnegie Institution for Science in Washington, D.C., was based on high-tech imagery gathered by an airplane flying over California earlier this year. It revealed that as many as 888 million large trees experienced “measurable losses of canopy water” since the drought began four years ago. Of those, as many as 58 million trees lost enough water to be considered “extremely threatening to long-term forest health.”

Researchers said the risk to California’s trees remains high even with heavy precipitation predicted this winter due to El Niño.

“The drought put the forests in tremendous peril, a situation that may cause long-term changes in ecosystems that could impact animal habitats and biodiversity,” said lead researcher Greg Asner, a Stanford University scientist, in a prepared statement.

The results, published in the Proceedings of the National Academy of Sciences, aren’t the first alarms sounded over the perilous state of California’s trees. A U.S. Forest Service survey in the spring showed that an estimated 12 million trees had died already due to a mix of drought and an infestation of bark beetles.

Gov. Jerry Brown, citing increased wildfire dangers, declared a state of emergency over California trees in October. The declaration called on state and local agencies to ramp up efforts to remove dead or dying trees.

“Recent scientific measurements suggest that the scale of this tree die-off is unprecedented in modern history,” he wrote in his declaration. He also appealed to the U.S. Department of Agriculture for help in dealing with the problem.

This story was originally published December 29, 2015 at 10:19 AM with the headline "California drought endangers millions of trees."