A new aerial survey conducted by the U.S. Department of Agriculture has identified, somewhat alarmingly, that there are now more than 102 million dead trees lining California's mountain forests. This new number revises a previous estimate from May by 36 million. In total, the Department of Agriculture believes approximately 62 million trees have died in California alone in 2016.
The news doesn't get better when we look to the future either. Millions more trees are expected to die off in the next couple months. A La Niña winter is expected to bering drier than average conditions to a state still wrestling with an epic drought.
Why are the trees dying? Well, obviously the drought has a lot to do with it, but the answer is a little bit more complicated, and has a lot to do with an infestation of invasive bark beetle species. Trees can weather droughts, as they have for millions of years before this most recent one. However, trees in drought conditions also produce much less sap than trees that receive an adequate amount of water. Sap acts as a defense for trees against the multitudes of little critters who love nothing more than chewing on wood. With less sap, however, the trees become more susceptible to attack by bugs and other invasive species. This current die-off is the product of an ill-timed coincidence between a boom in invasive beetle species, and a significant drought.
Bark beetles are usually kept in check by cold winters, something that, along with rain, California has been in short supply of. Without cold winter temperatures, the beetles continue to reproduce and continue to kill more trees.
"The scale of die-off in California is unprecedented in our modern history," said Randy Moore, an employee of the U.S. Forest Service, to the L.A. Times. The trees are dying “at a rate much quicker than we thought.”
And these aren't just ordinary trees, either. Many of the trees in California's evergreen forests in and around the Sierra Nevada are hundreds of years old. That so many of them have been lost so quickly is, ultimately, a tragic event that will not be remedied for at least several generations. The excess number of dead organic matter in California's forests also intensifies wildfires when they break out.
"These dead and dying trees continue to elevate the risk of wildfire, complicate our efforts to respond safely and effectively to fires when they do occur, and pose a host of threats to life and property across California," said Agriculture Secretary Tom Vilsack. "USDA has made restoration work and the removal of excess fuels a top priority, but until Congress passes a permanent fix to the fire budget, we can't break this cycle of diverting funds away from restoration work to fight the immediate threat of the large unpredictable fires caused by the fuel buildups themselves."
Good thing our next president believes in climate change. 😩
