Acid Rain -- Rainfall with a pH of less than 7.0. Long-term deposition of these acids is linked to adverse effects on aquatic organisms and plant life in areas with poor neutralizing (buffering) capacity.
Acre -- A measure of area equal to 43,560 square feet (4,046.87 square meters). One square mile equals 640 acres.
Acre-foot (af) -- The volume of water that will cover one acre to a depth of 1 foot.
Adaptive management areas -- Landscape units designated for development and testing of technical and social approaches to achieving desired ecological, economic, and other social objectives.
Biological corridor -- A habitat band linking areas of similar management and/or habitat type.
Blowdown -- Trees felled by high winds.
Board feet (BF) -- Lumber or timber management term. The amount of wood contained in an unfinished board 1 inch think, 12 inches long, and 12 inches wide.
Boreal Forest -- A northern forest, as in the boreal forest Biome, characterized by evergreen conifers and long winters. The boreal forest, also referred to as a Taiga, is found in the northern parts of North America, Europe, and Asia.
Buffer strip -- A barrier of permanent vegetation, either forest or other vegetation, between waterways and land uses such as agriculture or urban development, designed to intercept and filter out pollution before it reaches the surface water resource.
Canopy -- A layer of foliage in a forest stand. This most often refers to the uppermost layer of foliage, but it can be used to describe lower layers in a multistoried stand. Leavs, branches and vegetation that are above ground and/or water that provide shade and cover for fish and wildlife.
Canopy closure -- The degree to which the canopy (forest layers above one's head) blocks sunlight or obscures the sky.
Classic old growth -- Forest stands with unusually old and large trees that also meet criteria for old-growth forest.
Clear-cut -- A harvest in which all or almost all of the trees are removed in one cutting.
Clear-cut harvest -- A timber harvest method in which all trees are removed in a single entry from a designated are, with the exception of wildlife trees or snags, to create an even-aged stand.
Climax -- The culminating stage in plant succession for a given site where the vegetation has reached a highly stable condition.
Coarse woody debris (CWD) -- Portion of a tree that has falled or been cut and left in the woods. Usually refers to pieces at least 20 inches in diameter.
Conifer -- A tree belonging to the order Gymnospermae, comprising a wide range of trees that are mostly evergreens. Conifers bear cones (hence, coniferous) and needle-shaped or scalelike leaves.
Coniferous -- Pertaining to Conifers, which bear woody cones containing naked seeds.
Corridor -- A defined tract of land, usually linear, through which a species must travel to reach habitat suitable for reproduction and other life-sustaining needs.
Cover -- Vegetation used by wildlife for protection from predators, or to mitigate weather conditions, or to reproduce. May also refer to the protection of the soil and the shading provided to herbs and forbs by vegetation.
Crown -- The upper part of a tree or other woody plant that carries the main system of branches and the foliage.
Crown cover -- The degree to which the crowns of trees are nearing general contact with one another.
Cull -- A tree or snag that does not meet merchantable specifications.
Culvert -- A buried pipe that allows streams, rivers, or runoff to pass under a road.
Debris torrent -- Rapid movement of a large quantity of materials (wood and sediment) down a stream channel during storms or floods. This generally occurs in smaller streams and results in scouring of streambed.
Deciduous -- Trees and plants that shed their leaves at the end of the growing season.
Deciduous Plant -- (Botanical) (1) Plants characterized by a specific growth and dormancy cycle, with certain parts falling at the end of the growing period, as leaves, fruits, etc., or after anthesis, as the petals of many flowers. (2) Plants having leaves of this type. As contrasted with Evergreen which remains verdant throughout the year.
Decomposer -- Any of various organisms (as many bacteria and fungi) that feed on and break down organic substances (such as dead plants and animals).
Decomposition -- The breakdown of matter by bacteria and fungi, changing the chemical makeup and physical appearance of materials.
Down log -- Portion of a tree that has fallen or been cut and left in the woods.
Duff layer -- The layer of loosely compacted debris underlying the litter layer on the forest floor.
Early seral stage forest -- Stage of forest development that includes seedling, sapling, and pole-sized trees.
East-side forest -- The 12 National Forests in Washington, Oregon, and California that lie partly or wholly east of the Cascade Mountain Range crest: Colville, Deschutes, Fremont, Klamath, Malheur, Ochoco, Okanogan, Shasta-Trinity, Umatilla, Wallowa-Whitman, Wenatchee, and Winema National Forest.
Edge -- Where plant communities meet or where successional stages or vegetative conditions with plant communities come together.
Edge effect -- "The drastically modified environmental conditions along the margins, or ""edges,"" of forest patches surrounded partially or entirely by harvested lands."
Effective old-growth forest -- Old-growth forest largely unmodified by external environmental influences from nearby, younger forest stands.
Enhancement -- Emphasis on improving the value of particular aspects of water and related land resources.
Forest canopy -- The cover of branches and foliage formed collectively by the crowns of adjacent trees and other woody growth.
Forest fragmentation -- The change in the forest landscape, from extensive and continuous forests of old-growth to mosaic of younger stand conditions.
Forest land -- Land that is now, or is capable of becoming, at least 10 percent stocked with forest trees and that has not been developed for nontimber use.
Forest landscape -- Land presently forested or formerly forested and not currently developed for nonforest use.
Fragmentation -- The process of reducing size and connectivity of stands that compose a forest.
Grass/Forb -- An early forest successional stage where grasses and forbs are the dominant vegetation.
Herbaceous -- Vegetation or parts of plants with little or no woody tissue.
Instream cover -- The layers of vegetation, like trees, shrubs, and overhanging vegetation, that are in the stream or immediately adjacent to the wetted channel.
Landing -- Any place on or adjacent to the logging site where logs are assembled for further transport.
Landscape -- A heterogenous land area with interacting ecosystems that are repeated in similar form throughout.
Landscape diversity -- The size, shape, and connectivity of different ecosystems across a large area.
Landscape features -- The land and water form vegetation, and structures that compose the characteristic landscape.
Landslide -- A movement of earth down a steep slope.
Large woody debris -- Pieces of wood larger than 10 feet long and 6 inches in diameter, in a stream channel.
Late seral state forest -- Stage in forest development that includes mature and old-growth forest.
Leave strips -- Generally narrow bands of forest trees that are left along streams and rivers to buffer aquatic habitats from upslope forest management activities.
Litter layer -- The loose, relatively undecomposed organic debris on the surface of the forest floor made up typically of leaves, bark, small branches, and other fallen material.
Managed forest -- Any forestland that is treated with silvicultural practices and/or harvested.
Mass movement -- The downslope movement of earth caused by gravity. Includes but is not limited to landslides, rock falls, debris avalanches, and creep. It does not however, include surface erosion by running water. It may be caused by natural erosional processes, or by natural disturbances (e.g., earthquakes or fire events) or human disturbances (e.g., mining or road construction).
Old-growth associated species -- Plant and animal species that exhibit a strong association with old-growth forests.
Old-growth forest -- A forest stand usually at least 180-220 years old with moderate to high canopy closure; a multilayered, multispecies canopy dominated by large overstory trees; high incidence of large trees; some with broken tops and other indicators of old and decaying wood (decadence); numerous large snags; and heavy accumulations of wood, including large logs on the ground.
Overstory -- Trees that provide the uppermost layer of foliage in a forest with more that one roughly horizontal layer of foliage.
Rain Forest -- A tropical woodland that has an annual rainfall of at least 100 inches (254 centimeters) and often much more, typically restricted to certain lowland areas.
Reforestation -- The natural or artificial restocking of an area with forest trees.
Rootwad -- The mass of roots associated with a tree adjacent or in a stream that provides refuge and nutrients for fish and other aquatic life.
Silviculture -- The science and practice of controlling the establishment, composition, and growth of the vegetation of forest stands.
Snag -- Any standing dead, partially dead, or defective (cull) tree at least 10 inches in diameter at breast height and at least 6 feet tall.
West side forests -- The 11 National Forests in Washington, Oregon, and California that lie partly or wholly west of the Cascade Mountain Range crest. They are the Gifford Pinchot, Mendocino, Mt. Baker-Snowqualmie, Mt. Hood, Olympic, Rouge River, Siskiyou, Siuslaw, Six Rivers, Umpqua, and Willamette National Forests.
Wildfall -- Trees or parts of trees felled by high winds.
Wildlife tree -- A live tree retained to become future snag habitat.
Windthrow -- A tree or trees uprooted or felled by the wind.
Woodland -- Forest land producing trees not typically used as saw timber products and not included in calculation of the commercial forest land allowable sale quantity.
Woody debris -- Referring to wood in streams.