Tree Mortality and Our 12-Month Fire Season
By Richard Forster
It’s no secret that our Sierra Nevada forests are in big trouble. We have more than 66 million dead trees in the mountains and foothills of California—killed by a prolonged drought and an onslaught of bark beetles. The images from the Southern and Central Sierra are frightening. Acres and acres of pine trees are orange and brown, dead, dying, dry. And the bark beetles are moving north. As they kill entire stands of trees they move on to new sections of forest.
We are in our fifth consecutive drought year. The warmer winters and lack of adequate rainfall are all factors in bark beetle population explosions. The normal lifecycle for bark beetles is two or three hatches per year. The warmer weather we’ve had in the past several years has allowed four or five hatches, resulting in millions more beetles attacking the trees.
This slow but steady northward expansion shows no sign of stopping. And it leaves us vulnerable to a faster-moving calamity; the danger of wildfires. If our forests do catch fire, all the dead trees could fuel a fire that burns faster and hotter and is more devastating to people and property.