What is tree mortality?

Tree mortality means trees have died. Trees dying are a normal occurrence in natural ecosystems. The difference now is that the extended drought has caused an abnormally high number—in the millions—of trees in California’s forests and wildland-urban interface areas to weaken and/or die. Weakened trees are more susceptible to attacks from bark beetles. Once a tree is successfully invaded by bark beetles, there is no recovery for the tree; it will die.