Forest health monitoring in the United States: focus on national reports
The health and sustainability of United States forests have been monitored for many years from several different perspectives. The national Forest Health Monitoring (FHM) Program was established in 1990 by Federal and State agencies to develop a national system for monitoring and reporting on the status and trends of forest ecosystem health. We describe and illustrate the annual national reports which are one aspect of the Analysis and Reporting component of the FHM Program. The evolution of the content and format of reports from 2001 through 2013 has followed from changes in information requirements. Current practices are illustrated by using material drawn from the 2013 report which includes three sections covering forest health status and trends (insect, disease, fire, drought, and tree mortality), new techniques in forest health monitoring (disturbance mapping, invasive plants, and tree crown conditions), and special investigations to evaluate the possible causes or consequences of observed forest health conditions.