(Link to Metadata) The EcologicOther_ELT (Ecological Land Type) data layer was developed by the Green Mountain National Forest in the early 1980's from aerial photography. Using stereo-pairs of 1:42000 aerial photographs units were mapped using techniques similar to those used by soil scientists to delineate soil-series. After the initial mapping, fieldwork was done to 1) verify and adjust unit designations and 2) develop unit descriptions. To do this, sample plots were established on photos in locations that appeared to be representative of particular ELT's, or in locations where there were questions about the accuracy of the designations. Adjustments to the ELT boundaries were made in the field when data on vegetation and edaphic and topographic features were collected at sample plots. On the north half of the Green Mountain National Forest, 60 different elts have been mapped, and 320 sample plots established to validate and describe the units. Polygons were drawn onto 1:24000 USFS Topographic Maps sheets (mylar). In 1993 these maps were given to the University of Vermont's Spatial Analysis Lab for digitizing. Automation was completed in the fall of 1993. Ecological land classification (ELC) is a cartographic approach to forest land delineation that defines units of land at different spatial scales that are hierarchical, nested, and homogeneous in their environmental and late-successional vegetational characteristics. The ecological land classification system in use on the Green Mountain National Forest (GMNF) in Vermont conforms to the guidelines defined by the National Hierarchical Framework of Ecological Units established by the USDA Forest Service. This classification system is meant to assist managers by allowing them to delineate ecosystems, assess resources, conduct environmental analyses, establish desired future conditions, and manage and monitor resources. Units at the ecological land type (ELT) scale have been mapped on the GMNF. These units are designed to assist managers in site specific, project-level planning. Average unit size for ELT's on the north half of the GMNF is 267 acres. The units are identified by a four-digit code that is based on landtype association, geomorphic process, soil depth, and moisture (refer to ELTCODE documentation).
