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Items starting with O


A description of a desired condition for a resource. Objectives can be quantified and measured and, where possible, have established time frames for achievement. The objectives for a plan are the means of measuring progress toward achieving or maintaining desired conditions. Like desired conditions, objectives are aspirations and are not commitments or final decisions approving projects and activities (36 CFR 219.7).

Off-Highway Vehicle

Any motorized vehicle designed for or capable of cross-country travel on, or immediately over, land, water, sand, snow, ice, marsh, swampland, or other natural terrain; except that such term excludes (A) any registered motorboat, (B) any fire, military, emergency, or law enforcement vehicle when used for emergency purposes, and any combat or combat support vehicle when used for national defense purposes, and (C) any vehicle whose use is expressly authorized by the respective agency head under a permit, lease, license, or contract.


Off-Highway Vehicle

Old Growth

Old single story forest single canopy layer consisting of large or old trees. Understory trees are often absent, or present in randomly spaced patches. It generally consists of widely spaced, shade-intolerant species, such as ponderosa pine and western larch, and high frequency fire regimes. Old multi-story forest - a forest stand with moderate to high canopy closure, a multi-leveled and multi-species canopy dominated by large overstory trees; high incidence of large trees, some with broken tops and other indications of old and decaying wood; numerous large snags; and heavy accumulations of wood, including large logs on the ground.


Generally denotes that an area is available for a particular use or uses. Refer to specific program definitions found in law, regulations, or policy guidance for application to individual programs. For example, 43 CFR 8340.0-5 defines the specific meaning of 'open' as it relates to OHV use.

Organic Soil

Soil at least partly derived from living matter, such as decayed plant material.


Over Mature Timber

Trees that have attained full development, particularly in height, and are declining in vigor, health, and soundness.

Over-Snow Vehicle

A motor vehicle that is designed for use over snow and that runs on a track or tracks and/or a ski or skis, while in use over snow.


The upper canopy layer; the plants below comprise the understory.