3: Maintenance of forest ecosystem health and vitality

Defoliation can be caused by disease, physical force (extreme storms), and pest insects. Most trees can recover from defoliation, but it can be a serious source of stress and will reduce photosynthetic activity and growth.

Wildfires (and prescribed fires) can have positive consequences for ecosystems and communities. One positive consequence is that natural processes adapted to fires will benefit. Another is that vegetation mass will be reduced, reducing the fuels available for future fires.

High impact NIPS species are capable of having significant impacts on biological diversity, productive capacity, soil and water, and social well being. These impacts include out-competing native species, slowing timber regeneration and forage production, altering riparian shading and streambank morphology, and altering fire regimes affecting public heath and safety. (from the 2003 Forest and Rangeland Assessment)

Efficient and effective weed control programs and strategies are characterized by efforts that prevent invasions and quickly detect new occurrences so the species may be removed or contained before spreading. The California Department of Food and Agriculture’s (CDFA) Noxious Weed Prevention and Control Program works under the assumption that it is more cost effective to keep pests out of California than to address potentially widespread and ongoing infestations. The strategy for pest prevention is similar for all kinds of pests. There are four major parts: 1) keep a foreign pest from getting into California in the first place (exclusion); 2) if a pest does get in, find it while the population is still small (detection); 3) when such a population is found, remove it so California is once again free of the pest (eradication); and 4) inform the public of the importance of keeping California free of new pests. (from the 2003 Forest and Rangeland Assessment)

American agricultural policy has long recognized the threat to domestic farming and ranching from diseases introduced from other countries. Concerns over homeland security have heightened efforts to monitor the food supply chain. California’s livestock industry has undergone a variety of changes making it more susceptible to the spread of diseases such as foot-and-mouth disease and anthrax. These changes include factors such as greater concentrations of cattle in feedlots and nearby areas, and use of dairy related by-products as cattle feed. (fromt eh 2003 Forest and Rangeland Assessment)

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)

This simple metric reflects the proportion of a landscape that is forested.

Non-native animal species are also increasingly recognized as one of the principal threats to the maintenance of biological diversity. Overall, approximately 14 percent of California’s animal species (terrestrial and aquatic vertebrates) are established non-natives.

This indicator is best thought of as an index of condition, composed of multiple metrics that together give a measure of "health". The term health is most relevant when compared to reference conditions defined as healthy or unhealthy.

This indicator will provide tabular and map information on tree mortality in the state's forests. The first metric tracks tree mortality from all causes and data can be summarized by tree species. The second metric provides an overview of tree mortality from insects and diseases across the landscape on an annual basis.