Forest Pests, Invasive Plants, and Air Quality

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)

Native and non-native forest insects and diseases can kill thousands of trees in patches of outbreak. For example, the California oak borer, the goldspotted oak borer, tthe fruit tree leaf roller, sudden oak death, and Port Orford cedar root disease have all affected many acres of hardwood forest in California. The native pests and diseases are naturally-occurring, so concerns about them may be restricted to the effect of climate change on range of impact and mortality that might affect structures and communities built within forests.

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.

Report on and quantify recent efforts to combat the spread of forest health related insects and disease. This shows trends in the activity level of programs and agencies to address forest health issues. Area of affected forests treated by targeted purpose (stop spread of insect infestation, stop spread of non-insect related of diseases)

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.

Trends in air pollution have shown improvements due to new laws and regulations as well as improved technologies. These results show decreasing numbers of non-attainment days (days in which state air pollution maximums are exceeded) in several air basins for ozone and particulate matter greater than ten microns in size (PM10). Ozone levels remain a concern to forest and rangeland resources within the Sierra Nevada mountains and east of the San Joaquin Valley and South Coast air basins. Wide variations in air quality are found throughout these air basins. The primary source of ozone that drifts east into the Sierra Nevada mountains has been linked to the agricultural activity in the Sacramento and San Joaquin valleys via westerly air flows. (from the 2003 Forest and Rangeland Assessment)