They wanted information that would be comparable across Forest boundaries and interface with other Forest, regional and national databases. The primary objectives of the program are to help Forests meet federal and agency responsibilities for the detection and description of air pollution impacts and the protection of Forest air resources. Secondary objectives are to improve our understanding of the ecological roles of non-vascular plants and to develop their potential as indicators of forest health, stability and biodiversity. Plots are located on the USFS Forest Inventory Assessment grid system used for Current Vegetation Surveys, permanently marked in the field and entered in the GIS system of each Forest. Lichen inventory data are added to this database.
Forests choose priority areas for monitoring and intensity of sampling level.
Within each national forest, one-quarter of forested plots are monitored each year for four years. Monitoring rounds will be repeated every ten years. Each summer, specially trained field crews collect target lichens and mosses for tissue analysis at all plots. Concentrations of 27 elements are measured for approximately 10 species region-wide. The field teams also perform a complete survey of epiphytic macrolichens at each plot, including ocular abundance estimates.