Ecological Land Types

Personnel: James Bove, David Capen, Charles Ferree

Cooperators: Diane Burbank, Green Mountain National Forest, Gary Wade, Mark Twery, USDA Forest Service Northeastern Forest Experiment Station

What is ecological land classification?

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 (detailed table).

How were ecological land types delineated on the Green Mountain National Forest?

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 (map), and 320 sample plots established (map) to validate and describe the units.

Development of Ecological Databases

The ecological land classification system (ELC) in use by the USDA Forest Service is designed to assist land managers by classifying lands according to their inherent characteristics, potential uses, and productivity. A preliminary ELC developed for the Green Mountain National Forest in Vermont has not yet been validated with actual sample plot data. To validate the classification system, plot data has been collected on nearly 1000 sample plots throughout the national forest.

Vegetation Data

One-fifth acre circular plots (52.7 ft radius) were used to sample vegetation. Vegetation data were stratified into one of four groups according to life form: overstory trees, sapling/seedlings, shrubs, and ground flora, including herbs, ferns, mosses, and club mosses.

Physiographic and Edaphic Data

A soil pit was dug at each plot and described using standard soil survey techniques. Other physiographic and topographic data was collected as well (detailed table). Although this data was collected to meet a specific objective it offers countless opportunities to explore the relationships between soil-site attributes and vegetation. The data is publicly available. Contact for more information.

       Updated: 30 June 2000