Glossary of Terms

vertical diversity

The diversity in a stand that results from the different layers or tiers of vegetation.

viable population

The number of individuals of a species sufficient to ensure the long-term existence of the species in natural, self-sustaining populations that are adequately distributed throughout their range.

virgin forest

A natural forest virtually un-influenced by human activity.

visual quality objective

A set of measurable goals for the management of forest visual resources.

visual resource

A part of the landscape important for its scenic quality. It may include a composite of terrain, geologic features, or vegetation

Visual Resource Management (VRM)

A system for evaluating the visual resources of a given area and for determining what degree of protection, rehabilitation, or enhancement is desirable and possible.


Visual Resource Management

water table

The upper surface of groundwater. Below it, the soil is saturated with water.

water yield

The runoff from a watershed, including groundwater outflow.


The entire region drained by a waterway (or into a lake or reservoir. More specifically, a watershed is an area of land above a given point on a stream that contributes water to the streamflow at that point.


Areas that are permanently wet or are intermittently covered with water.

Wilderness Area

An area of public land designated by an Act of Congress to be protected in its natural condition according to the requirements of the Wilderness Act of 1964 with the following characteristics: (1) It generally appears to have been affected primarily by the forces of nature, with the imprint of man's work substantially unnoticeable; (2) It has outstanding opportunities for solitude or a primitive and unconfirmed type of recreation; (3) It has at least five thousand acres of land or is of sufficient size as to make practicable its preservation and use in an unimpaired condition; and (4) It may also contain ecological, geological, or other features of scientific, educational, scenic or historical value (Wilderness Act, Sec. 2(c)).

Wilderness Characteristics

Identified by congress in the 1964 wilderness act; namely size, naturalness, outstanding opportunities for solitude or a primitive and unconfined type of recreation, and supplemental values such as geological, archeological, historical, ecological, scenic, or other features. It is required that the area possess at least 5,000 acres or more of contiguous or be of a size to make practical its preservation and use in an unimpaired condition; be substantially natural or generally appear to have been primarily by the forces of nature, with the imprint of man being substantially unnoticeable; and have either outstanding opportunities for solitude or a primitive and unconfined type of recreation.

Wilderness Inventory Areas (WIA)

These areas are found in Utah that were not made into WSA's but citizens inventoried and found wilderness characteristics. During the Clinton Administration, the BLM re-inventoried these lands, completed in 1999, and found Wilderness characteristics on these lands.

Wilderness Study Area (WSA)

Created by the BLM through the inventory process of the Federal Land Policy and Management Act (FLPMA), which required the BLM to inventory lands under its management authority for wilderness quality and protect those lands until Congress decides whether or not to designate the land as Wilderness.

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