Forest Dynamics in the Southern Lake Tahoe Basin, 1940–2002

This map shows areas of land-cover change in the southern Lake Tahoe Basin that were identified through postclassification change detection of multitemporal land-use/land-cover datasets for four dates: 1940, 1969, 1987, and 2002. The land-use/land-cover datasets were derived through visual interpretation of large-scale historical digital orthophotos and IKONOS multispectral imagery using a hierarchical classification system and a one-acre minimum mapping unit. In areas where more than one change was detected during the 62-year study period, the most recent change is shown.

The most significant changes that occurred in naturally vegetated areas were changes in forest density, forest loss, forest encroachment, and tree mortality caused in part by timber harvest for local use, fire suppression, fuels reduction activities, and environmental stresses. These results are part of continuing research by the U.S. Geological Survey Geography Discipline to quantify and analyze trends in development, land management, and forest succession during the most intensive urbanization period for the Lake Tahoe Basin.