Jane Braxton Little, HIGH COUNTRY NEWS
…at the heart of the logging debate is the question of whether dead trees are a fire hazard. The conventional assumption is that insect outbreaks increase wildfire risk because dead trees are more flammable than green ones. That is a conclusion most scientists have long disputed.
Looking north from Blue Canyon near Shaver Lake, copper-colored forests blanket mountain slopes that stretch ridge after ridge to the horizon. The patches of fading green that dappled these hillsides last fall have merged into an unbroken cover of rust-needled pines. At dusk, when the winds die down, an eerie stillness gives way to the muffled sound of munching as beetles chomp through one tree after another, thousands after thousands.
This is the look — and the sound — of drought.
Four consecutive winters with little to no snowpack, followed by four dry summers, have devastated California’s southern Sierra Nevada. At least 66 million trees are already dead statewide, and millions more are expected to die as the drought persists into a fifth summer.
On the Sierra National Forest, up to 90 percent of the mid-elevation ponderosa pines are dead. Weakened by drought, oaks are succumbing to sudden oak death along the central and northern coast, and the disease has moved into the Central Valley. Pines gray as ghosts haunt coastal, Cascade and Sierra foothills. The epidemic is spreading across choice vistas owned by millionaires as well as remote landscapes rarely entered by humans.
And the bark beetles that caused this desolation? They’re reproducing at triple the normal rate. Forest ecologists used to consider them a natural part of the forest dynamic — and they are. Stressed by drought and decades of air pollution in overcrowded stands, however, the natural chemicals trees pitch out in self-defense can’t keep up with the onslaught of bugs. No one is calling what’s happening here natural anymore.
“Nobody imagined this would come on as fast as it has, or be as lethal,” says Craig Thomas, conservation director for Sierra Forest Legacy, a coalition focused on Sierra Nevada national forest issues. “And nobody really knows what the hell to do.”
Overwhelmed by the die-off, forest management agencies are resorting to a century-old strategy: removing dead trees to minimize future wildfires, which they predict will be inevitable and cataclysmic. Gov. Jerry Brown declared a state of emergency in October, citing a public safety hazard from falling trees and worsening wildfire risks. The tree mortality task force he convened has marshaled a small army to log over 6 million acres.