Sampling Design of the U.S. National Forest Health Monitoring Program : National Forest Inventories

1993

S. 150-157

8 Lit. Ang.

Unselbständiges Werk

200103947

The USDA Forest Service, U.S. Environmental Protection Agency, state, and other agencies initiated the Forest Health Monitoring (FHM) Program in 1990. The objectives are to monitor the current status and trends in forest ecosystem conditions in response to pollutant exposure. The FHM Program is part of a larger Environmental Monitoring and Assessment Program (EMAP). The sampling design used in FHM is based on the EMAP grid of 12,600 hexagons across the continental United States. At each grid point, a 40-km¬ hexagon is to be characterized by a variety of remotely sensed and map-based descriptors. A cluster of plots is visited on the ground in each hexagon. The cluster is composed of a series of nested fixed-radius plots at four points. Clusters are located on both forest and nonforest lands. Observations are made on site conditions, soils, tree size and visual symptoms, foliar chemistry, and vegetativ structure. A pilot study of 40 clusters in 1990 has shown the cluster design to be adequate and efficient for a variety of attributes.