Forest land is defined as land with at least 10% of its surface area covered by trees of any size or formerly having had such trees as cover and not currently built-up or developed for agricultural use. The USDA Forest Service's Forest Health Monitoring (FHM) program is the lead organization for monitoring and reporting on the health of the Nation's forested ecosystems. Forests cover between 29% and 32% of the total U.S. land area. The target population for FHM's sampling design is all of the forested land in the United States (Figure at left). Currently (1998) FHM is sampling in 28 states. EMAP- Forest was a partner in FHM from 1990 to 1995. Currently EMAP is working with FHM in the Mid-Atlantic Integrated Assessment (MAIA). For more information on the FHM program, refer to the FHM homepage.