Forest Inventory and Analysis National Program

Program Features

Forest Health Indicators

The forest monitoring component is the best-known component of the FIA program. This component consists of a three stage systematic sample of sites across all forested lands of the US. Phase 1 consists of remote sensing for stratification, to identify where the forested land is. Phase 2 consists of one field sample site for every 6,000 acres of forest, where field crews collect data on forest type, site attributes, tree species, tree size, and overall tree condition. Phase 3 consists of a subset of Phase 2 sample plots which are measured for a broader suite of forest health attributes including tree crown conditions, lichen community composition, understory vegetation, down woody debris, and soil attributes. Soil samples are sent to a laboratory for chemical analysis. Finally, an associated sample scheme exists to detect cases of ozone damage occurring to adjacent forest vegetation.

Collectively, the forest monitoring component of FIA provides a nationwide systematic sample of a wide array of measurements on forested ecosystems, which are used by a diverse set of customers for many purposes. For example, FIA data have been used to map habitat for endangered animal species, to identify areas of forest decline, and to track the effect of global change reflected in changing species distributions.

In additional to producing a variety of reports and analyses at the state and regional level, information from the FIA forest monitoring program is publicly available through our online FIA database.

To learn more about the Forest Health Indicators click on indicator pictures below or links above.