Forestry Glossary

Artificial Regeneration - The growth of new trees through seeding and planting.

Basal Area - The cross-sectional area in square feet of a tree trunk measured at 4.5 feet above the ground.

Basal Area Factor – Number of units of basal area per acre represented by each tree.

Best Management Practices - Procedures employed during harvesting and/or timber stand improvement activities that reduce erosion and prevent or control water pollution.

Board Foot - A unit of wood measuring 1-inch in thickness by 12-inch in width by 12 inches in length or its equivalent.

Buck - To cut the bole of a tree into log lengths for transport.

Cambium - A thin layer of specialized cells within a tree’s trunk that divide to produce new inner bark cells to the outside and new sapwood cells to the inside. The narrow band of cells that is responsible for the tree’s growth in circumference.

Canker - An imperfection on the trunk, limb or twig of a tree caused by an organism that kills a part of the tree's tissue. Canker causing organisms sometimes exist in some sort of a balance with the host, never killing enough tissue to cause death. Cankers tend to weaken trees at the points where they are growing causing the tree to eventually break.

Canopy - A layer or multiple layers of branches and foliage at the top of a forest's trees. The collection of individual tree crowns is the canopy.

Carbon Sequestration – The uptake and storage of carbon. Trees and plants, for example, absorb carbon dioxide, release the oxygen and store the carbon.

Carrying Capacity - The maximum number or biomass of organisms of a given species that can be sustained or survive on a long-term basis within an ecosystem.

Chain - A distance of 66 feet.

Clear-Cut Harvest - A harvest and regeneration practice that removes all trees within a given area. Used most commonly in forests that require full sunlight to regenerate or areas where young forests are the preferred habitat.

Clinometer - An instrument used to measure height of a tree.

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

Conservation - Planned management and wise use of natural resources for present and future generations.

Conservation Easement - A legally enforceable transfer of usage rights for the purposes of conserving land and prohibiting real estate development.

Cord - A stack of compactly piled round or split wood consisting of 128 cubic feet measuring 4 feet in height by 4 feet in width by 8 feet in length.

Cost-Share Assistance - An assistance program offered by various state and federal agencies that pays a fixed rate or percentage of the total cost necessary to implement some forestry or agricultural practice.

Crop Tree - Tree selected for quality, species, size, timber potential, or wildlife value that is favored for growing to final harvest.

Crown - The branches and foliage at the top of an individual tree.

Crown-Class - A tree classification system based on the tree's relative height, foliage density, and ability to intercept light. Crown-class measures past growth performance and calls attention to crop trees that could benefit from future thinning and harvest operations. There are four classifications:

Dominant Trees - Larger-than-average trees with broad, well-developed crowns. These trees receive direct sunlight from all sides and above.

Codominant Trees - Average-to-fairly large trees with medium-sized crowns that form the forest canopy. These trees receive full light from above but are crowded on the sides.

Intermediate Trees - Medium-sized trees with small crowns below the general level of the canopy. Intermediate trees receive little direct light, are poor crop trees, and should be removed during thinning operations.

Suppressed Trees- Small trees that grow below the tree canopy and receive no direct sunlight from any direction.

Cull - A tree or log of marketable size that is useless for all but firewood or pulpwood because of crookedness, rot, injuries, or damage from disease or insects.

Deck (Decking) - A centralized location where harvested trees are collected and loaded onto trucks. Logging decks need to be carefully maintained to control runoff and erosion.

Defect - Characteristics of a tree that may decrease its value for lumber. These can include rot, scars, or crooked stems.

Den tree - A tree that has a hole in its stem that can be used as shelter by wildlife such as birds and small mammals.

Dendrology – The study of trees and their identifying characteristics.

Diameter at Breast Height (DBH) - The diameter of a tree measured in inches at breast height 4.5 feet above the ground.

Disking - Preparing a site for reseeding or planting by plowing the ground with disks to mix organic material into the soil. This method may also be used to encourage regrowth of native understory plants.

Ecological Succession - The gradual change of plant and animal communities over time.

Ecosystem - A loosely defined area consisting of numerous habitats.

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

Ephemeral stream - A stream that runs intermittently in response to precipitation or snowmelt. An ephemeral stream lacks a well-defined channel.

Even-Aged Management - A forest management method in which all trees in an area are harvested at one time or in several cuttings over a short time to produce stands that are all at or near the same age.

Forest Management Plan - Written guidelines for current and future management practices recommended to meet an owner’s objectives.

Forest Type - Groups of tree species commonly growing in the same stand because their environmental requirements are similar.

Forester – Professional with experience in a broad range of forest-related topics including forest and wildlife ecology, economics, legal issues, and the growing and harvesting of forest products. Like an architect designing a building, a forester designs the harvest plan.

Forestry - The art and science of managing forests to produce various products and benefits including timber, wildlife habitat, clean water, biodiversity and recreation.

Geotextile - A synthetic material placed beneath road fill and used to confine the road aggregate and to distribute the weight of the load.

Girdling - A physical cutting or disruption of the cambial sap flow that often results in tree mortality.

Grade - In reference to logs and lumber, a designation of quality which, together with species and size, determines the value of a given piece in a particular market.

Group Selection - A specific type of silvicultural practice resulting in the removal of small groups of trees in order to regenerate shade-intolerant trees.

Habitat - An area in which a specific plant or animal naturally lives, grows and reproduces; the area that provides a plant or animal with adequate food, water, shelter and living space.

Hardwoods (Deciduous Trees) - Trees with broad, flat leaves shed on an annual basis whose wood hardness varies among individual species.

Heartwood - The central core of a tree, which is made up of dense, dead wood and provides strength to the tree.

High-Grading – An exploitive harvesting technique that removes only the largest, most valuable trees from a stand and provides high returns at the expense of future growth potential. Sometimes referred to as selective cutting.

Improvement Cut - An intermediate silvicultural treatment made to improve the form, quality, heath, or wildlife potential of the remaining stand.

Increment borer - A T shaped tool consisting of a bit, a handle and an extractor that is used to measure the age or growth rate of a tree. The bit is hollow and when turned into the tree, cuts a pencil shaped piece of wood showing the growth rings.

Indicator Species – A species used in combination with others to identify the presence of a specific assemblage, community or association.

Intermittent stream - A stream with a well-defined channel that has water flowing during the wet season.

Invasive Species - An organism that is nonnative (or alien) to an ecosystem and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.

Inventory - Quantitative method used to estimate the actual volume, composition, and market value of standing timber.

Keystone Species – A species that plays an important ecological role in determining the overall structure and dynamic relationships within a biotic community.  A keystone species presence is essential to the integrity and stability of a particular ecosystem. 

Landing - A cleared area in the forest to which logs are yarded or skidded for loading onto trucks for transport.

Limiting Factor - Any requirement for wildlife survival that is in limited supply.

Live Crown Ratio (LCR) - The ratio of the length of the tree’s crown (upper portion of the tree consisting of healthy, green foliage) to its total above ground height. Often reported as percentage, LCR is an indicator of tree health.

Log Rule or Log Scale - A table based on a diagram or mathematical formula used to estimate volume or product yield from logs and trees. Three commonly used rules and scales in the United States are International, Scribner and Doyle.

Logger (Timber Harvester) - Someone in the business of cutting down trees, cutting them into logs, removing the logs from the woods to the roadside and transporting the logs to the sawmill. Like a builder following the architect’s design, a logger implements the harvest plan created by the forester.

Lump Sum Sale - The sale of specified timber on a specified area for one total price

Marking - The physical process of selecting trees to be cut or left during a harvest accomplished normally by spraying paint on a prominent part of the tree.

Mast - Fruits or nuts used as a food source by wildlife.

MBF - Abbreviation denoting one thousand board feet that is a typical unit of volume for saw logs and manufactured wood products. (It takes 11 MBF of wood to build an average 1,900-square-foot house.)

Merchantable Height - The stem length, normally measured from the ground to a specified top diameter, above which no other saleable product can be cut. Diameter, local markets, limbs, knots, and other defects collectively influence merchantable height.

Multiple Use - The management of land or forest for more than one purpose, such as wood production, water quality, wildlife, recreation, aesthetics, or clean air.

Nonpoint Source Pollution - Water pollution frequently caused by water runoff from different sources and locations. Best management practices (BMPs) can be used to help control nonpoint source pollution

Nontimber Forest Products - All forest products except timber, including resins, oils, leaves, bark, plants other than trees, fungi, and animal or animal products.

Perennial stream - A stream that has a well-defined channel and flows year-round, except during times of extreme drought.

Phloem - The part of a tree that carries sap from the leaves to the rest of the tree. Also called inner bark.

Photosynthesis - The process by which a plant or tree combines water and carbon dioxide with energy from the sun to make glucose and oxygen.

Point Sampling - A method of inventorying a forested area based on tree size to determine basal area of a stand. Samples are taken using a prism or angle gauge to determine which trees will be counted in the inventory. Point sampling does not require direct measurement of tree diameter or plot area.

Pole - A tree of 4" to 10" DBH, not large enough to be considered sawtimber; also, a stand whose trees average this size (as in polestand or poletimber stand)

Pulpwood - Wood used in the manufacture of paper, fiberboard, or other wood fiber products. Pulpwood-sized trees are usually a minimum of 4 inches in diameter.

Regeneration Cut – Any silvicultural practice with the intent to reestablish a new stand of seedlings.

Release - To free a tree from competition with its immediate neighbors by removing the surrounding trees. This occurs naturally and artificially.

Residual Stand - Trees left in a stand to grow until the next harvest.

Rip-rap - Rock or other large material used to protect against runoff and for erosion control

Riparian Forest or Riparian Buffers - Vegetative areas along a body of water

Root Collar - The transition zone between stem and root at the ground line of a tree or seedling.

Rotation - The number of years required to establish and grow trees to a specified size, product, or level of maturity.

Salvage Cut - The harvesting of dead or damaged trees or of trees in danger of being killed by insects, disease, flooding, or other factors.

Sapling - A small tree, usually between 2 and 4 inches diameter at breast height.

Sawlog or Sawtimber - Trees normally over 10" DBH that can be sawn into boards; or stands with trees averaging this size.

Scale Sale – Selling of timber on a periodical basis as it is cut, usually by species. 

Scarifying - The disturbance or removal of the top litter layer of soil in order to prepare a site for planting.

Sedimentation - The deposition or settling of soil particles transported by water.

Seedling - A tree, usually less than 2 inches diameter at breast height.

Seed Tree Cut - A harvesting method in which a few scattered trees are left in the area to provide seed for a new forest stand. Selection of seed trees should be based upon growth rate, form, seeding ability, wind firmness, and future marketability.

Seed Year - A year in which a given species produces a large seed crop over a sizable area.

Selective harvest – A user-defined term that means only that someone designated trees for harvest.

Shade-Intolerant Species - Trees that require full sunlight to thrive and cannot grow in the shade of larger trees.

Shade-Tolerant Species - Trees that have the ability to grow in the shade of other trees and in competition with them.

Shelterwood Harvest - Removing trees on the harvest area in a series of two or more cuttings so new seedlings can grow from the seed and in the partial shade of older trees.

Silvics - Biological characteristics of individual trees that determine how they will grow and reproduce.

Silviculture - The art, science and practice of establishing, tending and reproducing forest stands of desired characteristics. It is based on knowledge of species’ characteristics and environmental requirements.

Single Tree Selection – The removal of individual trees under uneven-aged regeneration methods.

Site Index - A relative measure of forest site quality based on the height of the dominant trees at a specific age (usually 25 or 50 years, depending on rotation length).

Skid Trail - A temporary, unsurfaced path used by loggers to drag cut trees from the stump to the logging deck. Skid trails need to be carefully maintained to control runoff and erosion.

Skidder - A specialty tractor that is used to haul logs out of a forest once they are cut.

Skidding/Forwarding – Dragging/Transporting fallen trees along the forest floor; during harvest, trees are skidded to the logging deck, where they are loaded on trucks for transport.

Slash - Tree tops, branches, bark, or other residue left on the ground after logging or other forestry operations.

Snag - A snag is a dead tree that can be a very valuable wildlife resource.

Softwoods (Conifer Trees) — Trees that are usually evergreen, bear cones, and have needles or scale-like leaves such as pine, spruce, fir, and cedar.

Stand - An easily defined area of the forest that is relatively uniform in species composition, age structure and condition and can be managed as a single unit.

Stocking - A description of the number of trees, basal area, or volume per acre in a forest stand compared with a desired level for balanced health and growth.

Stumpage – The value of trees as they stand uncut in the woods (on the stump).

Succession - The somewhat predictable sequence of plant community replacement beginning with bare ground and resulting in a final relatively stable community.

Sustainable Forestry - A holistic, conservation ethic based on environmental balance and health that helps ensure forests will be managed in ways that have the potential to meet the social, physical and economic needs of the present while ensuring similar options for the future. This includes a suite of policies, plans and practices that seeks to sustain an array of forest benefits at a particular location.

Sustained Yield - Management of forestland to produce a relatively constant amount of wood products, revenue, or wildlife.

Thinning – An intermediate silvicultural practice that reduces tree density and competition between trees in a stand.

Timber Cruise - A survey of forestland to locate timber and estimate its quantity by species, products, size, quality, or other characteristics.

Timber Stand Improvement (TSI) - Improving the quality of a forest stand by removing or deadening undesirable species to achieve desired stocking and species composition.

Transpiration - The loss of water through leaves.

Understory - The layer formed by the crowns of smaller trees in a forest.

Uneven-Aged Management - The practice of managing a forest by periodically selecting and harvesting individual trees or groups of trees from the stand while preserving its natural appearance.

Volume - Refers to the amount of wood in a tree or log. Expressed as board feet, cubic feet, cords or other measure.

Water Bar - A diagonal ditch or hump in a trail that diverts surface water runoff to minimize soil erosion.

Windrow - A pile or row of slash material left over after logging operations or site preparation; often later burned.

Windthrow - When trees are uprooted by strong winds or during a storm.

Xylem - The part of a tree that transports water and nutrients up from the roots to the leaves. Older xylem cells become part of the heartwood. Also called sapwood.