Glossary

Abiotic stress

Stress induced by the non-living component of the environment.

Blowdown

Tree or trees felled or broken off by wind.

Boreal forest

One of the three main forest zones in the world located in northern regions and is characterized by the predominance of conifers.

Climate change

An alteration in measured quantities (e.g., precipitation, temperature, radiation, wind and cloudiness) within the climate system that departs significantly from previous average conditions and is seen to endure, bringing about corresponding changes in ecosystems and socioeconomic activity.

Commercial forest

Forest land that is able to grow commercial timber within an acceptable time frame and is designated for such a purpose.

Crown fire

A fire that advances through the crown fuel layer, the upper part of the tree bearing live branches and foliage.

Duff layer

A general term referring to the litter and humus layers of the forest floor.

Ecosystem

A dynamic system of plants, animals and other organisms, together with the non-living components of the environment, functioning as an interdependent unit.

Even-aged

Of a forest stand or forest type in which relatively small age differences exist between individual trees (usually 10 to 20 years).

Functional genomics

Predicting biological function of genes and proteins from their primary sequence.

Gap dynamics

The change in space and time in the pattern, frequency, size, and successional processes of forest canopy gaps caused by the fall or death of one or more canopy trees.

Genotype

An individual hereditary constitution derived from its parents and forming a unique combination of genes; sometimes referring to trees having similar genetic constitutions with regard to certain common, identifiable, genetic characteristics, expressed in distinctive features.

Greenhouse gases

Those gases, such as water vapour, carbon dioxide, tropospheric ozone, nitrous oxide and methane, that are transparent to solar radiation but opaque to longwave radiation. Their action is similar to that of glass in a greenhouse.

Hardwood (deciduous tree)

Tree whose leaves are not persistent and fall off at the end of a defined growing season or during a period of temperature or moisture stress.

Holistic approach

Broad brush approach based on a theory according to which a whole cannot be analyzed without considering the sum of its parts or reduced to discrete elements.

Ladder fuels

Fuels that provide vertical continuity between the surface fuels and crown fuels in a forest stand, thus contributing to the ease of torching and crowning, e.g., tall shrubs, small-sized trees, bark flakes, tree lichens.

Mop-up (fire)

The act of extinguishing a fire after it has been brought under control.

Non-timber forest products

Any commodity obtained from the forest that does not necessitate harvesting trees. Includes game animals, fur-bearers, nuts and seeds, berries, mushrooms, oils, foliage, medicinal plants, peat and fuelwood, forage, etc.

Prescribed burning

The knowledgeable application of fire to a specific land area to accomplish predetermined forest management or other land use objectives.

Seed tree (method)

A tree left standing for the sole or primary purpose of providing seed.

A method of regenerating a forest stand that involves removing all of the trees from an area in a single cut, except for a small number of seed-bearing trees. The objective is to create an even-aged stand.

Slash burning

Intentional burning of debris resulting from timber harvesting operations, where the fuel has not been piled or windrowed, allowing the fire to spread freely over the entire harvested area.

Smouldering fire

A fire burning without flame and barely spreading.

Softwood

Cone-bearing tree with needles or scale-like leaves that is the predominant tree type in coniferous forests.

Stand

A continuous group of trees sufficiently uniform in age-class distribution, composition and structure, and growing on a site of sufficiently uniform quality, to be a distinguishable unit.

Succession

Changes in species composition in an ecosystem over time, often in a predictable order.

Sustainable forest management

Management that maintains and enhances the long-term health of forest ecosystems for the benefit of all living things while providing environmental, economic, social and cultural opportunities for present and future generations.

Understorey

The lower level of vegetation in a forest. Usually formed by ground vegetation (mosses, herbs and lichens), herbs and shrubs, but may also include subdominant trees.

Uneven-aged

A stand with trees of three or more distinct age classes, either intimately mixed or in small groups.

Value-added product

Adding value to a product by further processing it. Examples of value-added wood products include joinery stock, windows, doors, kitchen cabinets, flooring and mouldings. Value-added pulp and paper products include such items as packaging, diapers, coated papers, tissue, business papers and stationery, and other consumer paper products.

Water bombing

The act of dropping suppressants (water or short-term retardant) on a wildfire from an aircraft in flight.

Watershed

The area drained by an underground or surface stream, or by a system
of streams.