Glossary

Afforestation – Planting trees on land that was previously used for crops or pasture.

Allowable error – The desired width of the confidence interval expressed as a percentage of the mean. For instance, the CCX has suggested that an allowable error of ±10% at the 90% confidence level is a good statistical target.

Accuracy – The closeness of a measurement or estimate to the true value.

Basal area – The cross-sectional area of a single tree stem, including bark, measured at breast height, or the sum of the cross-sectional areas of all stems in a stand measured at breast height and expressed per unit of land area.

Bias – A systematic distortion that is introduced through sampling, measurement, or estimation processes.

Biomass – Material that is derived from living, or recently living biological organisms. In the forestry context, it can refer to
• live trees (both above and below ground components: including bole, bark, branches, foliage, and roots)
• understory vegetation (tree seedlings, shrubs, herbs, forbs, and grasses)
• standing dead trees (above and below ground components)
• down dead wood (down woody debris, stumps, and dead roots)
• forest floor (fine woody debris, litter, humus)
Biomass is generally reported as oven-dry weight (tons).

Breast height – Standardized point for measuring tree diameters; defined as 4.5 ft above ground.

Carbon credits – A “carbon credit” is a market term. Carbon storage in trees is usually measured in carbon dioxide equivalent (CO2e). Trees are roughly 50% carbon, based on dry weight. A carbon credit is equal to one metric ton of CO2e. Therefore, the amount of carbon credits in a forest stand can be computed based on a forest inventory cruise designed to determine the timber volume by weight.

Carbon cycle – The cycle by which carbon in various forms moves between the various components of the Earth’s biosphere, between the atmosphere, hydrosphere (seas and oceans), lithosphere (rocks, soils and mineral deposits, including fossil fuels) and biological material including plants and animals. Carbon is constantly moving between some of these forms, maintaining a state of dynamic equilibrium.

Carbon sequestration – The removal and long-term storage of carbon from the atmosphere. Trees capture carbon through photosynthesis by taking in CO2 from the air, breaking it down, storing the carbon in all parts of the tree, and releasing the oxygen back into the atmosphere. Fast-growing trees are an efficient way to sequester atmospheric carbon

Coefficient of variation – An estimate of relative variability in a population. It is calculated as the ratio of the standard deviation to the mean and is usually expressed as a percentage value.

Confidence limit – Forest inventory estimates can be expressed as a range – the confidence interval, bounded by confidence limits – within which the population parameter is expected to occur at a given probability.

Crown – the branches and foliage of a tree.

Crown ratio – The ratio of the length of live crown to total tree height.

Cruise – A forest survey conducted to obtain inventory information such as estimating the quantity of timber on a given area according to species, size, quality, and other characteristics.

Cull – A tree that has no merchantable value as a result of poor shape or damage from injury, insects or disease.
Diameter at breast height (dbh) – standard measurement of a tree’s diameter, usually taken at 4 1/2 feet above the ground.

Edge – the boundary between two ecological communities, for example, between field and woodland or between a young forest stand and an old forest stand.

Edge effect – The modified environmental conditions or habitat along the margins or edges of forest stands or patches.

Even-aged – Forest stand composed of trees of the same, or approximately the same, age.

Forestry – The science of planting, managing and protecting forests.

Geographic Information System (GIS) – An information management system that accommodates the entry, storage, manipulation, retrieval, and display of spatial data.

Inventory – An itemized list or catalogue of goods, property, etc.

Forest inventory – A survey of a forest area to determine such data as area, condition, timber, volume and species for specific purposes such as planning, purchase, evaluation, management or harvesting.

Map projection – A mathematical model for converting locations on the Earth’s surface from spherical to planar coordinates.

Mean – The average value of a set of observations, obtained by dividing the sum of all observations in the set by the total number of observations.

Multi-aged – Forest stand that has more than one distinct age class arising from specific disturbance and regeneration events at various times.

Map scale – The ratio of the distance measured on the map to the distance measured on the ground (measurements must be in the same units).

Overstocked – the situation in which trees are so closely spaced that they compete for resources and do not reach full growth potential.

Parameter – A characteristic which describes the whole or part of a population in some way.

Pool – Pools are comprised of multiple projects. Pools may or may not be geographically grouped. They are generally built with the dual goals of minimizing risk and increasing efficiency. A carbon aggregator, such as Woodlands Carbon, aggregates (bundles) woodland owner’s yearly carbon growth together into carbon credit pools and then trades the pools on the open market. By pooling owners together, Woodlands Carbon creates access to various markets.

Population – In a statistical sense, a population is an assembly of all possible individuals (units, measurements, observations, etc.) that meet a specified and well-defined objective.

Precision – The closeness of a series of measurements or estimates to their own average.

Project – Projects are defined as groupings of stands enrolled in the offset program by an individual forest owner. Some buyers requires that all eligible properties of an ownership must be enrolled, i.e., a woodland owner cannot enroll just a portion of their forest.

Range – The difference between the largest and smallest value in a set of observations.

Regeneration – the process by which a forest is reseeded and renewed. Advanced regeneration refers to regeneration that is established before the existing forest stand is removed.

Reforestation – Planting trees on land that was previously forested, but which has lost forest cover due to major disturbances or events that are not the result of management decisions or neglect.

Sample – A part of a population selected and measured as representative of the whole to estimate characteristics of the whole population.

Site – the combination of biotic, climatic, topographic, and soil conditions of an area.

Site index – A measure of the quality of a site based on the height of dominate trees at a specified age (usually 25, 50, or 100 years), depending on the species.

Stand – A contiguous 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.

Stand – A group of forest trees of sufficiently uniform species composition, age, and condition to be considered a homogeneous unit and distinguishable from adjacent units.

Stand density – A quantitative measure of stem crowding within a stocked area.

Stand table – A tabulation of the total number of stems (or average number of stems per acre) in a stand or compartment by dbh classes and species.

Standard deviation – A measure of the dispersion about the mean of a population or a sample; computed as the square root of the variance.

Stocking – Refers to the adequacy of a given stand density to meet some management objective.

Stock table – A tabulation of the total volume of stems (or average volume per acre) in a stand or compartment by dbh classes and species.

Stratum – A grouping of similar stands as defined by forest cover type, tree size, and stocking level. The key to good stratification is to ensure that the parameters of interest are more alike within each stratum than in the sample population as a whole.

Tree taper – The decrease in diameter of a tree stem or log from the base upwards or from the larger diameter end to the smaller end in logs.

Type mapping – The process of delineating soil, vegetation, or site quality types on an aerial photograph or on a base map.

Understocked – A stand of trees so widely spaced, that even with full growth potential realized, crown closure will not occur.

Uneven-aged – Forest stand composed of an intermingling of trees that differ markedly in age.

Variance – A statistical measure of the dispersion of individual observations about their arithmetic mean; a measure of variability in a population or sample.

Well-stocked – The situation in which a forest stand contains trees spaced widely enough to prevent competition yet closely enough to utilize the entire site.