Acre
An area of land measuring 43,560 square feet (.4 ha)

Annual
Plant that lives or grows for only one year or growing season

Artificial Regeneration
The process of renewing a forest through planting.

Basal Area
The area in square meters (square feet) of the cross section at breast height of a single tree or of all the trees in a hectare (acre). Most commonly used as an indicator of stand density expressed as square metres/hectare (square feet/acre).

Biodiversity
The diversity of plants, animals, and other living organisms in all their forms and levels of organization.

Canopy
Cover of branches and foliage formed by tree crowns, which shades that protects lower forest layers and provides habitat.

Cavity Trees
Living or dead trees with natural or excavated holes or cavities.

Clearcut
The removal of all trees, regardless of size, from an area.

Codominant Trees
Trees with crowns forming the general level of the forest canopy that receive full light from above but comparatively little from the sides; usually with medium sized crowns more or less crowded on the sides.

Commercial Thinning
A thinning operation that produces commercial material, at least to the value of the direct cost of the operation.

Competition
The struggle between trees to obtain sunlight, nutrients, water, and growing space. Every part of a tree - from the roots to the crown - competes for space and food.

Coniferous
Commonly called softwood or evergreen. Trees that have cones and keep their needles throughout the winter. There are some exceptions.

Cord
A stack of round or split wood, with or without bark, consisting of 128 cubic feet of wood, and air space. A standard cord measures 4 feet by 4 feet by 8 feet.

Crop Tree
Any tree forming, or selected to form, part of the final harvest. Crop trees may be selected from an immature stand and carried through until final harvest.

Crown
The branches and foliage at the top of a tree.

Cruise
A survey to locate and estimate the quantity of timber on a given area by species, products, size, quality, or other characteristics.

Deciduous
Commonly referred to as hardwoods or broad leaf trees. In most cases, they lose their leaves in the fall.

Density
The number of trees per hectare (acre).

Dominant Trees
Trees with crowns extending above the general level of the canopy and receiving full light from above and partial light from the sides; larger than the average trees in the stand with well-developed crowns.

Edge
The transition between two different types or ages of vegetation.

Evenaged Stand
A stand of trees with maximum age differences of 10-20 years and of approximately the same height.

Fauna
Animal life.

Flora
Plant life.

Habitat
The natural home environment of a plant or animal.

High-Grading
Selective cutting where only the biggest, best and most valuable trees are harvested.

Immature Stand
A stand of young trees past the regeneration stage usually showing good health and vigour.

Intermediate Trees
Trees with crowns below but still extending into the general level of the forest canopy, receiving a little direct light from above but none from the sides; usually with small crowns that are shaded on all sides.

Intolerant
The inability of a tree to maintain health and vigour under shade. Intolerant trees require full sunlight to maintain vigorous growth. Referred to as pioneer species.

Mature Stand
A stand of trees is considered mature when height, diameter and volume growth level off. Different species mature at different ages.

Mixed Stand
A timber stand in which less than 80 percent of the trees in the main canopy are of a single species.

Natural Stand
A stand of trees grown from natural seed fall or sprouting.

Pre-Commercial Thinning
A thinning treatment carried out in a young natural stand that removes competition and undesired trees.

Regeneration
The reforestation or reproduction of the forest by either natural seeding or artificial means.

Release Cut
The removal of competing vegetation and/or trees so that favoured young growth can benefit from more light and growing space.

Rotation
The period of years required to establish and grow timber crops to a specified condition of maturity – from harvest cut to harvest cut.

Salvage Cut
The harvesting of dead or damaged trees, or of trees in danger of being killed by insects, disease, flooding, or other factors in order to save their economic value.

Selection Cut
A silvicultural system that involves the periodic removal of trees, individually or in small groups, from an unevenaged forest in order to realize the yield and establish a new crop.

Shelterwood Cut
An evenaged silvicultural system in which, in order to provide a source of seed and/or protection for regeneration, the old stand (the Shelterwood) is removed in two or more successive shelterwood cuttings.

Silviculture
The art, science, and practice of cultivating forest crops.

Site Capability
An expression of a particular area's ability to support forest growth. The better capability, the greater the rate of height and growth volume.

Site Preparation
An operation to expose mineral soil, mix mineral soil with humus, reduce competition from plants, and compact logging slash to make planting easier and generally improve the site in which the individual trees are to be planted or seeded.

Snag
A standing dead tree from which most of the leaves and branches have fallen.

Special Management Zone
An area of forest required to be established adjacent to a watercourse to protect the watercourse and bordering wildlife habitat.

Stand
A group of trees being sufficiently uniform to be distinguised from adjacent groups and be considered a silvicultural entity.

Stand
A group of trees with similarities in species composition, height/diameter distribution, and age composition.

Stands
Groups of trees being sufficiently uniform as to be distinguised from adjacent groups and be considered silvicultural entities.

Stocking
An indicator of how well the site is occupied by trees. Expressed as basal area per hectare (acre) it is a measure of the portion of a hectare (acre) occupied by stems. Expressed as percent of crown closure, it is an estimate of how well the site is used.

Succession
Natural replacement of one plant community by another over time.

Suppressed Trees
Trees with their crowns entirely below the general forest canopy that receive no direct light either from above or from the sides.

Sustainable
Meeting the needs of today without sacrificing the ability to meet the needs of future generations.

Thinning
Cutting in an immature stand to improve quality, improve species composition, obtain greater merchantable yield, or recover material that may be lost otherwise.

Tolerance
The ability of a tree to maintain health and vigour under shade from other trees. Very tolerant tree species can grow in dense shade.

Understory
Bushes, shrubs, woody plants and young trees reaching up to the forest canopy.

Unevenaged Stand
A stand of trees with considerable age differences representing at least three age classes. Unevenaged stands contain large, older trees as well as immature trees.