In forest ecosystems, insects naturally consume living and dead vegetation. Climate change, fire suppression, land management activities, and other influences can cause outbreaks of insects outside the normal range. Much of California’s forests are at high risk to mortality from native and non-native pest damage (greater than 25 percent tree mortality expected). Given current management regimes and fire suppression tactics, stocking levels on many forests are very high. With increased stocking levels, host materials accumulate making some areas susceptible to insect and disease attacks. accumulate making some areas susceptible to insect and disease attacks. (adapted from 2003 Forest and Rangeland Assessment)