Tree crown conditionThis article is part of a larger document. View the larger document here.
The crown-condition indicator was originally developed in 1990 to monitor tree crown health. The indicator presently consists of seven “absolute” variables recorded in the field (sapling vigor class, uncompacted live crown ratio, crown light exposure, crown position, crown density, foliage transparency, and crown dieback), and four “composite” variables formulated from multiple crown dimensions (crown volume, crown surface area, crown shape, and crown efficiency). Detailed descriptions of the crown-condition indicator are available in Schomaker and others (2007) and on the Web at http://srsfia2.fs.fed.us/crowns/. Between 1990 and 1999, the national Forest Health Monitoring (FHM) Program of the Forest Service, U.S. Department of Agriculture, collected crown data as part of the FHM Detection Monitoring (DM) system (Riitters and Tkacz 2004). In 2000, upon integration of the FHM plot system with the phase 3 plot network (Bechtold and Patterson 2005) of the Forest Inventory and Analysis (FIA) Program of the Forest Service, FIA assumed responsibility for collecting crown data.