Variability in older forest structure in western Oregon

The goal of this report is to assist Federal land managers in developing realistic structural targets for young forests for which the development of late-successional and old-growth (LSOG) characteristics is a long-term management objective (i.e., in Late-Successional Reserves established under the Northwest Forest Plan). A unique LSOG structural database was created using complete inventories, or censuses (i.e., 100% timber cruise records), of all conifer trees > 1 ft diameter from 586 recently harvested older forests on five Bureau of Land Management (BLM) districts in western Oregon. The average area of each of the 586 inventoried older forests, 28.1 ac, clearly reflected the spatial scales typical of forest management units on Federal lands covered by the Northwest Forest Plan. All told, the LSOG database contains conifer tree census data for over 16,400 ac of LSOG forests. Ecoregion-level variability in LSOG forest structure was compared and contrasted for sites contained in the LSOG database. The spatial variability of trees and snags at 14 LSOG sites was characterized using structural data collected along one or more long (396-2178 ft) belt transects at each site.