Forestry Glossary

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Aesthetics – forest value, rooted appreciation, affording inspiration, contributing to the arts, and providing a special quality of life.

Afforestation – the establishment of forest trees by planting or seeding an area not previously forested.

Alluvial soils – soil formed from material such as gravel, sand, of water and showing little of no modification of the original material by soil forming processes.

Area sensitive species – plants or animals with very specific habitat requirements that are susceptible to population decline when their habitat is altered.

Aspect – the orientation of a slope with respect to the compass; the direction toward which a slope faces; north facing slopes are generally cooler than south facing slopes.


Basal area – is a measurement of the cross-sectional area of a tree trunk in square feet at breast height. If a forest stand is the sum of the individual trees, and is reported as BA per acre.

Biological diversity – the variety of plants and animals, the communities they form and the ecological functions they perform at the genetic, stand, landscape, and regional levels.

Biological maturity – the point in the life cycle of a tree at which there is not net biomass accumulation; the stage before decline when annual growth is offset by breakage and decay.

Board foot – a unit of wood 1 inch thick, 12 inches long, and 12 inches wide. One board foot contains 144 cubic inches of wood.

Bole – the main trunk of a tree.

Browse – portions of woody plants including twigs, shoots, and leaves used as food by such animals as deer.

Buffer strips – forestland left relatively undisturbed to lessen visual or environmental impacts of timber harvesting, usually along a road or waterway.


Canopy – the upper level of a forest, consisting of branches and leaves of taller trees. A canopy is complete (or has 100 percent cover) if the ground is completely hidden when viewed from above the trees.

Clearcutting – a harvesting and regeneration technique that removes all the trees, regardless of size, on an area in one operation. Clearcutting produces an even-aged forest stand.

Cobblestone – a rounded or partly rounded fragment if rock, 3 to 10 inches in diameter.

Corridor – a strip of wildlife habitat, unique from the landscape on either side of it, that links one isolated ecosystem”island” (eg., forest fragment) to another. Corridors allow certain species access to isolated habitat areas, which consequently contributes to the genetic health of the populations involved.

Covet – geographic unit of cover for wildlife (usually game); for example, a thicket or underbrush sheltering grouse or deer.

Crop tree – a term traditionally reserved to describe a tree of a commercially desirable species, with the potential to grow straight, tall, and vigorously. However, a crop tree can be one selected for non-timber purposes (varying with landowner objectives), such as mast production or den tree potential.

Crown class – an evaluation of an individual tree’s crown in relation to its position in the canopy and the amount of full sunlight it receives. The four recognized categories are: 10

dominant (D), co-dominant (C), intermediate (I), and overtopped or suppressed (S).

Cull – a tree of such poor quality that it has no merchantable value in terms of the product being cut. However, a timber cull tree may have value for wildlife or aesthetics.


dbh – diameter at breast height, or 4.5 feet above ground level. The abbreviation generally is written without capital letters and without periods.

Den tree – a tree with cavities in which birds, mammals or insects such as bees may nest (also known as cavity tree).

Diameter-limit cut – a timber harvesting treatment in which all trees over a specified diameter may be cut. Diameter limit cuts often over time reduce the quality of a forest stand significantly.

Disturbance – a natural or human-induced environmental change that alters one or more of the floral, faunal, and microbial communities within an ecosystem. Timber harvesting is the most common human disturbance. Windstorms and fire are examples of natural disturbance.


Economic maturity- the point in the life cycle of a tree or stand when harvesting can be most profitable, i.e., when the rate of value increase of an individual tree or stand falls below a desired alternative rate of return.

Ecosystem – a natural unit comprised of living organisms and their interactions with their environment, including the circulation, transformation, and accumulation of energy and matter.

Edge – the boundary between open land and woodland or between any two distinct ecological communities. This transition area between environments provides valuable wildlife habitat for some species, due to increase predation and parasitism.

Emergent wetlands – a class of wetland dominated by grasses, sedges, rushes, forbs, and other rooted, water-loving (possibly broad-leaved) herbaceous plants that emerge from water or soil surface; marshes are an example.

Endangered species – species in danger of extinction throughout all or a significant part of their range. Protection mandated by the United States Endangered Species Act, 1973.

Even-aged stand – a group of trees that do not differ in age by more than 10 or 20 years or by 20 percent of the rotation age.


Forest – a biological community dominated by trees and other woody plants.

Forest types – associations of tree species that commonly occur because of similar ecological requirements.

Examples of major forest types are oak-hickory, northern hardwoods, Allegheny hardwoods and spruce-fir.

Forested wetland – an area characterized by woody vegetation over 20 feet tall where soil is at least periodically saturated with or covered by water.

Fragipan – a dense and brittle pan, or layer, or soils. Its hardness results mainly from extreme density or compactness rather than from high clay content. The material may be dense enough to restrict root, nutrient, and water penetration.


Girdling – a method of killing unwanted trees by cutting through the living tissues around the 11

bole. Can be used instead of cutting to prevent felling damage to nearby trees. Girdled trees can provide cavities and dead wood for wildlife and insects.

Glacial till – the unsorted part of glacial drift, consisting of clay, silt, sand, and boulders transported and deposited by ice.


Habitat – the geographically defined area where environmental conditions (e.g., climate, topography, etc.) meet the life needs (e.g., food, shelter, etc.) of an organism, population, or community.

Hardpan –a cemented or hardened soil horizon. This layer, which may be of any texture, is compacted or organic matter, or other substances.

High-grading- a type of timber harvesting in which larger trees of commercially valuable species are removed with little regard for the quality, quantity, or distribution of trees and regeneration left on the site; often results when a diameter limit harvest is imposed.


Improvement cut – any cutting treatment used to alter species composition and tree spacing to realize ownership objectives. Thinning is a type of improvement cut.


Mast – all fruits of trees and shrubs used as food for wildlife. Hard mast includes nutlike fruits such as acorns, beechnuts, and chestnuts. Soft mast includes the fleshy fruits of black cherry, dogwood, and serviceberry.


Neo-tropical birds – birds that breed in the northern hemisphere during summer months, and winter in tropical regions (e.g., woodthrush or barn swallows).


Old-growth – forests that approximate the structure, composition, and functions of native forests prior to European settlement. They vary by forest type, but generally include more large trees, canopy layers, standing snags, nativespecies, and dead organic matter than do young or intensively managed forests.


Permeability, soil – the quality that enables water or air to move through the soil. Terms used to describe permeability are very slow, slow, moderate, rapid, and very rapid.

Pole stand – a stand of trees with dbh ranging from5 to 11 inches.


Reaction, soil – the degree of acidity or alkalinity of the soil, expressed in pH values or words.

Regeneration – the replacement of one forest stand by another as a result of natural seeding, sprouting, planting, o rother methods; also young trees which will develop into the future forest.

Regeneration cut – a timber harvest designed to promote and enhance natural establishment of trees. Even-aged stands are perpetuated by three types of regeneration cuts: seed tree, shelterwood, and clearcutting. Uneven-aged stands are perpetuated by selecting individual or small groups of trees for removal (e.g., the selection system).

Release – removal of overtopping trees to allow understory or overtopped trees to grow in response to increased light. 12

Residual stand – trees remaining following any cutting operation.

Riparian zone – an area adjoining a body of water, normally having soils and vegetation characteristics of floodplains or areas transitional to upland zones. These areas help protect the water by removing or buffering the effects of excessive nutrients, sediments, organic matter, pesticides, or pollutants.


Salvage cut – the removal of dead, damaged, or diseased trees with the intent of recovering value prior to deterioration.

Sapling – a small tree, usually defined as being between 1 and 5 inches dbh.

Sawlog – a log large enough to yield lumber. Usually the small end of a sawlog must be at least 6 to 8 inches in diameter for softwoods and 10 to 12 inches for hardwoods.

Second growth – the forests re-establishment following the removal of virgin (i.e., previously unharvested) or old-growth stands. Much of New York’s forests are either second or third growth.

Seed tree cut – a regeneration cut where mature trees are left standing in a harvested area to provide seed for regeneration of the cut-over site.

Seedling – a young tree originating from seed that is less than 4 feet tall and smaller than 2 inches in diameter at ground level.

Selection cut – a regeneration cut designed to create and perpetuate an uneven-aged forest. Trees may be removed singly or in small groups. A well-designed selection cut removes trees of lesser quality and trees in all diameter classes along with merchantable and mature high-quality sawlog trees. Should be differentiated from “select” cuts, which often equate to high-grading.

Shelterwood – a regeneration cut designed to stimulate reproduction by removing all overstory trees. This is achieved by a series of cuts over several years. Gradual reduction of stand density protects understory trees and provides a seed source for stand regeneration.

Silviculture – the art, science, and practice of establishing, tending, and reproducing forest stands.

Site – the combination of biotic, climatic, topographic, and soil conditions of an area; the environment at a location.

Site quality – the inherent productive capacity of a specific location (site) in the forest affected by available growth factors (light, heat, water, nutrients, anchorage); often expressed as tree height at a given age.

Slash – branches, tops, and cull trees left on the ground following a harvest. Although some of this material can be used for firewood, slash may be arranged in brush piles to provide wildlife cover. Left scattered, slash can protect seedling and sprouts from deer browsing and reduce soil erosion.

Snag – standing dead tree with few branches, or the standing portion of a broken-off tree. Snags may provide feeding and/or nesting sites for wildlife.

Species richness – the number of species present in a community or a defined area.

Spring seep – is a class of wetland created by groundwater emerging on lower slopes in small pools surrounded by vegetation. These create snow-free zones critical for wildlife feeding during winter.

Stand – a grouping of vegetation sufficiently uniform in species composition, age, and condition to be distinguished from surrounding vegetation types and managed as a single unit. 13

Stewardship – the wise management and use of forest resource to ensure their health and productivity for the future with regard for generations to come.

Stumpage – the commercial value of standing trees.

Succession – the natural series of replacements of one plant community (and the associated fauna) by another over time and in the absence of disturbance.


Texture, soil – is the relative proportions of sand, silt, and clay particles in a mass of soil.

Thinning – removal of trees to encourage growth of other selected individual trees. This may be commercial or pre-commercial.

Timber cruising – the process of estimating the quality, quantity, and characteristics of trees in a forest.

Timber stand improvement (TSI) – a combination of intermediate treatments designed to improve growth and composition of the forest; often spoken of as TSI.

Tolerance – a characteristic of trees that describes the relative ability to thrive with respect to the growth factors (light, heat, water, nutrients, anchorage). For instance, a “shade tolerant” species may thrive at low light levels.


Understory – the smaller vegetation (shrubs, seedlings, saplings, small trees) within a forest stand, occupying the vertical zone between the over story and the herbaceous plants of the forest floor.

Uneven-aged stand – a group of trees of various ages and sizes growing together on a site.


Watershed – a region or area defined by patterns of stream drainage. A watershed includes all the land from which a particular stream or river is supplied.

Wetlands – area which are either transitional between land and water (where the water table is at or near the land surface) or areas of land which are covered by shallow

Wolf tree – a large, excessively branchy tree which occupies more space in the forest than surrounding trees. Wolf trees have high wildlife and aesthetic value, but little if any timber value.

Water holding capacity – is the ability of soil to hold water that will not drain away but can be taken up by plant roots.

Water table – is the upper limit of the part of the soil or underlying rock material that is wholly saturated with water. In some places an upper, or perched, water table may be separated from a lower one by a dry zone.