Aspen Maps for the Broader Lake Tahoe Area

Maps of aspen (Populus tremuloides) percent cover from above (PCFA), produced using machine learning and Landsat spectral reflectance.

See Stewart and Long (2024) for more information:

Stewart J.A.E. & Long J.W. 2024. Distribution and Apparent Decline of Aspen (Populus tremuloides) in the Broader Lake Tahoe Area: A Four-Decade Assessment. Tahoe Science Advisory Council (TSAC), Incline Village, NV.

File Organization

To avoid data loss from reprojection, maps are provided in the native USGS Landsat grid projections within our project area, which spans two UTM zones (30-m resolutions, origins at 15, 15). Each map is composed of two GeoTIFF files, with suffixes _z10 and _z11 indicating their UTM zones (Zone 10N and Zone 11N, respectively).

Percent Cover From Above

Percent Cover From Above (PCFA) refers to the proportion of ground area covered by aspen canopies as seen from an aerial perspective. This metric is useful for assessing the extent and density of aspen stands. Understory vegetation cover that is not visible from aerial views due to obstruction by taller trees is not included in PCFA.

Model Name Conventions

Model versions are consistently labeled to reflect the data inputs and algorithms used. For example, 4.6.LS4to9.Ensemble.T02 indicates model version 4.6, Landsat satellites 4 to 9, ensemble modeling approach, and a 2% threshold applied to the xgb component model. See Stewart and Long (2024) for more information.