Module 1: Introduction to Silviculture

Glossary of Key Terms - Module 1

ACADIAN FOREST: The Acadian Forest is one of 12 forest regions in Canada. It is characterized by red spruce, balsam fir, maple and yellow birch.

ARTIFICIAL REGENERATION: Establishing a forest by direct seeding and/or planting.

BASAL AREA: The area in square meters (square feet) of the cross section of the trunk of a tree at breast height. Most commonly used as an indicator of stand density and is expressed as square metres/hectare (square feet/acre).

BIODIVERSITY: The variety of life in all its forms, levels and combinations. Includes ecosystem diversity, species diversity and genetic diversity.

BIOLOGICAL: Characteristics of living organisms which influence their growth and health.

BLOWDOWN: Trees uprooted by high winds, commonly called windthrow.

BREAST HEIGHT: The standard height, a distance 1.3 meters (4.5') above ground level, where the diameter of a standing tree is measured.

BUDS: Undeveloped shoot, leaf, or flower enclosed in protective scales. Terminal buds are located at the end of a twig. Lateral buds are located below the terminal bud and along the sides of the twig.

CANOPY: Cover of branches and foliage formed by tree crowns

CLEARCUT: The removal of all or most merchantable trees from an area.

CODOMINANT: Trees with crowns in the general level of the canopy which receive full light from above, but comparatively little from the side. Trees have medium-sized crowns.

CONES: The fruiting bodies of coniferous trees which produce the seed.

CONIFEROUS TREES: Commonly called softwood or evergreen, trees that have cones and keep their needles throughout the winter, except for tamarack.

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

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.

DISTRIBUTION: The arrangement of stand characteristics such as height, age, diameter and species.

DOMINANT: Trees with crowns extending above the general level of the canopy and receiving full light from above and partial light from the sides. They are larger than the average trees of the stand with well developed crowns.

DUFF: The shallow layer of organic soil and litter of the forest floor which lies over the general mineral soil.

ECOSYSTEM: An ecosystem consists of a dynamic set of living organisms (plants, animals and microorganisms) all interacting among themselves and with the environment in which they live (soil, climate, water and light).

EVEN-AGED STAND: A stand of trees with maximum age differences of 10-20 years and of approximately the same height.

FOREST: A group or community of trees and plants divided up into forest stands.

FOREST ECOLOGY: The relationship between forest organisms (plants and animals) and their environment.

GENETIC: The inherent physiology and development of living organisms as determined by the genes.

GERMINATION: The growth process of a mature seed, characterized by the emergence of a stem and root.

GROUND VEGETATION: Non-woody vegetation under 1.2 metres (4') in heigh.

HIGH-GRADING: Harvesting the biggest, best and most profitable trees and leaving the less desirable trees. May result in the growth of a poor quality stand. Also called selective harvesting.

HUMUS: Black or brown material found in soil, formed by partial decomposition of plant or animal material (organic matter).

IMMATURE STAND: A stand of young trees past the regeneration stage usually showing good health and vigor.

INTERMEDIATE: Trees with crowns extending into canopy formed by dominant and codominant trees which receive a little light from above, but not from the sides.

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.

LATERAL ROOTS: Relatively shallow roots which spread outward from the tree parallel to the ground.

LAYERING: A method of reproduction in which living lower branches come in contact with moist ground or are covered with litter and produce roots. These branches eventually grow into trees separate from the parent tree. It is a common reproduction method of black spruce.

LEADER: the main shoot of a tree. Will form the trunk as the tree grows

LOAM: A loose soil composed of clay, sand, and organic matter, often highly fertile.

LITTER: The top layer of debris (fallen leaves, needles, flowers, bark...) on the forest floor.

MATURE STAND: A trees is considered mature when height, diameter and volume growth level off. Different species mature at different ages.

MINERAL SOIL: Soil containing a high percentage of inorganic material such as rock, sand, clay, and silt.

NATURAL REGENERATION: Renewal of trees by natural seeding, sprouting, suckering, or layering.

ORGANIC SOIL: Soil containing a high percentage of dead or decaying plant matter (also called organic material) from fallen material such as needles and leaves, slash and blowdown.

PIONEER SPECIES: The first species to grow following a natural disturbance like fire or a harvest. These species are shade intolerant and normally short-lived. Common pioneer tree species in Nova Scotia are pin cherry, trembling aspen and red maple.

PRECOMMERCIAL THINNING: A spacing treatment carried out in young naturally regenerated stands which removes competition and concentrates growth on desired trees.

PURE STAND: A stand with at least 80% of the trees in the main canopy are of a single species.

REGENERATION: The reforestation or reproduction of the forest by either natural seeding or artificial means. Generally refers to established seedlings.

RESIDUAL TREES: Scattered, standing trees left by harvesting in an area which has undergone extensive harvesting.

ROTATION: The period of years to establish and grow timber crops to a specified condition of maturity from regeneration to final harvest.

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.

SELECTIVE HARVESTING: Harvesting the biggest, best and most profitable trees and leaving the less desirable trees. Also called high grading.

SHADE TOLERANCE: Shade tolerance refers to a tree’s ability to survive and grow in shaded conditions

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.

SPECIES: A category of individuals thought of as a group because of common qualities and characteristics.

SPROUTING: A form of natural regeneration that occurs when the main stem is removed. Dormant buds in the stump begin to grow into new shoots (for example red maple).

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

STAND STRUCTURE: The distribution of tree species and their age, height, species composition, diameter, and density of a specific area.

STOCKING: A relative term usually expressed as a percentage which refers to the number of trees that occur in a given area. An area that supports sufficient trees to optimally use all the available growing space is said to be 100% stocked. An area where only half of the available growing space is occupied by trees is said to be 50% stocked.

STUMPAGE: The price paid to the owner of standing timber, before the trees are harvested.

SUCKERING: Sprouting up from the roots, usually after a disturbance. Occurs in species with shallow rooted hardwoods such as red maples, beech and trembling aspen.

SUPPRESSED: Trees below general level of the canopy receiving no light either from the sides or above.

TAP ROOT: A deep root growing down into the ground which helps anchor the tree and maintain a water supply in dry soils.

TOLERANCE / TOLERANT: The ability of a tree to regenerate and maintain health and vigor under shaded conditions. Very tolerant tree species can grow in dense shade.

UNEVEN-AGED STAND: A stand trees with considerable age differences representing at least three age classes. Uneven-aged stands contain large, older trees as well as immature trees.

WINDTHROW: Tree(s) uprooted by wind, commonly called blowdown.