Common Forestry Terms
The following definitions have been provided by the Nova Scotia Department of Lands and Forestry Woodlot Management Home Study Glossary
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The British Columbia Ministry of Forests and Range Glossary of Forest Terms
Basal area (BA) is the area in square metres (or square feet) of the cross section of the trunk of a tree at breast height (1.3 m or 4.5 ft). It is most commonly used as an indicator of stand density and is expressed as square metres per hectare or square feet per acre.
Biodiversity The variety of life in all its forms, levels and combinations. Includes ecosystem diversity, species diversity and genetic diversity.
Canopy Cover of branches and foliage formed by tree crowns
Crown closure refers to “the stand condition resulting in the crowns of trees touching and effectively blocking sunlight from reaching the forest floor. Crown closure is expressed as a percentage.” (British Columbia Ministry of Forests and Range Glossary of Forestry Terms, 2008).
Density (stand) A measurement of the stand in terms of square metres of basal area, number of trees, or volume per hectare. It reflects the degree of crowding of stems within the stand. Expressed as basal area, it is a measurement of the portion of an area occupied by trees at breast height. Expressed as percentage of crown closure, it is an estimate of the extent the site is occupied.
Growing stock All the trees growing in a forest or in a specified part of it, generally expressed in terms of the number of volume or density.
Immature Stand A stand of young trees past the regeneration stage but not yet mature usually showing good health and vigor. Immature stands are typically over 15 years (past the regenerating stage).
Intolerant The inability of a tree to maintain health and vigor under shade. Intolerant trees require full sunlight to maintain vigorous growth. Referred to as pioneer species.
Mature Stand A trees is considered mature when height, diameter and volume growth level off. Different species mature at different ages at which time they begin bearing viable seed.
Merchantable (commercial) A tree, or stand that has attained sufficient size, quality and/or volume to make it suitable/economically feasible for harvest.
Non-forest Any land cover type that is not primarily intended for growing or supporting a forest.
Over Mature A tree or an even-aged stand that has reached a stage of development where growth, vigour and health are declining as it reaches the end of it’s natural life.
Operable (workable) Areas of land that are available for harvest based on factors that limit the work that can be done in that area. Such as rough terrain, wet ground, accessibility, etc.
Pre-Commercial Thinning A spacing treatment carried out in young naturally regenerated stands which removes competition and concentrates growth on desired trees.
Regeneration The reforestation or reproduction of the forest by either natural seeding or artificial means (planting). Generally, this refers to established seedlings.
Regenerating Stand is a forest stand that has been harvested of merchantable trees within the last 15 years and is in a regenerating state.
Residual Trees Scattered, standing trees left by harvesting in an area which has undergone extensive harvesting. Residual trees can be of any size/age.
Selection Harvest The removal of the trees of all sizes or a range of sizes, either as single, scattered individuals or in small groups as relatively short intervals repeated indefinitely. The continuous establishment of new trees and uneven-aged stands is encouraged.
Shade Tolerance Shade tolerance refers to a tree’s ability to survive and grow in shaded conditions
Shade intolerant Referring to trees that do not grow well in the shade
Example: white birch, trembling aspen
Shade Mid-tolerant Referring to trees that can grow in partial shade but cannot reach maximum potential in this condition.
Example: eastern white pine, yellow birch
Shade tolerant Referring to trees that can grow and establish in full shade.
Example: red spruce, eastern hemlock
Shelterwood Cut The removal of the mature timber in a series of cuttings which extend over a relatively short portion of the rotation. The establishment of Even-aged reproduction is encouraged under the partial shade of seed trees.
Site Capability An expression of a particular area’s ability to support forest growth. Expressed as volume/area/year. The better capability, the greater the rate of height and growth volume.
Silviculture Is the art and science of attempting to control or manipulate the establishment, growth, composition, health and quality of a forest to meet the diverse needs and values of the landowners.
Stand A group of trees, with similarities in species composition, height/diameter distribution, and age composition as well as similar site and soil conditions.
Stand Structure The distribution of tree species and their age, height, species composition, diameter, and density of a specific area.
Windthrown Tree(s) that is(are) uprooted by the wind.
Uneven-Aged Stand (multi-aged) A stand of trees with age differences representing at least three age classes. Uneven-aged stands contain large, older trees as well as immature trees.