Definitions

Indicative definitions taken from the Report of the ad hoc technical expert group on forest biological diversity

Terms Definitions
Forest The group considers the FAO definition of a forest as the basic one (FAO, 1998; FRA 2000), but acknowledge that many other useful definitions of "forest" exist in published form. The fact that "forest" has been defined in many ways is a reflection of the diversity of forests and forest ecosystems in the world and of the diversity of human approaches to forests.In this document, a forest is a land area of more than 0.5 ha, with a tree canopy cover of more than 10%, which is not primarily under agricultural or other specific non-forest land use.In the case of young forests or regions where tree growth is climatically suppressed, the trees should be capable of reaching a height of 5 m in situ, and of meeting the canopy cover requirement.
Forest biome This reflects the ecological and physiognomic characteristics of the vegetation and broadly corresponds to climatic regions of the Earth. In this document, it is used in reference to boreal, temperate and tropical forest biomes.
Forest type Within biomes, a forest type is a group of forest ecosystems of generally similar composition that can be readily differentiated from other such groups by their tree and undercanopy species composition, productivity and/or crown closure.
Forest ecosystem A forest ecosystem can be defined at a range of scales.It is a dynamic complex of plant, animal and micro-organism communities and their abiotic environment interacting as a functional unit, where trees are a key component of the system. Humans, with their cultural, economic and environmental needs are an integral part of many forest ecosystems.
Forest biological diversity Forest biological diversity means the variability among forest living organisms and the ecological processes of which they are part; this includes diversity in forests within species, between species and of ecosystems and landscapes.
Primary forest A primary forest is a forest that has never been logged and has developed following natural disturbances and under natural processes, regardless of its age.It is referred to "direct human disturbance" as the intentional clearing of forest by any means (including fire) to manage or alter them for human use. Also included as primary, are forests that are used inconsequentially by indigenous and local communities living traditional lifestyles relevant for the conservation and sustainable use of biological diversity. In much of Europe, primary forest has a different connotation and refers to an area of forest land which has probably been continuously wooded at least throughout historical times (e.g., the last thousand years). It has not been completely cleared or converted to another land use for any period of time. However traditional human disturbances such as patch felling for shifting cultivation, coppicing, burning and also, more recently, selective/partial logging may have occurred, as well as natural disturbances. The present cover is normally relatively close to the natural composition and has arisen (predominantly) through natural regeneration, but planted stands can also be found.However, the suggested definition above would include other forests, such as secondary forests.
Secondary forest A secondary forest is a forest that has been logged and has recovered naturally or artificially.Not all secondary forests provide the same value to sustaining biological diversity, or goods and services, as did primary forest in the same location.In Europe, secondary forest is forest land where there has been a period of complete clearance by humans with or without a period of conversion to another land use. Forest cover has regenerated naturally or artificially through planting.
Old growth forest Old growth forest stands are stands in primary or secondary forests that have developed the structures and species normally associated with old primary forest of that type have sufficiently accumulated to act as a forest ecosystem distinct from any younger age class.
Plantation forest A plantation forest may be afforested land or a secondary forest established by planting or direct seeding.A gradient exists among plantation forests from even-aged, single species monocultures of exotic species with a fibre production objective to mixed species, native to the site with both fibre and biodiversity objectives. This gradient will probably also reflect the capability of the plantation forest to maintain "normal" local biological diversity.
Degraded forest A degraded forest is a secondary forest that has lost, through human activities, the structure, function, species composition or productivity normally associated with a natural forest type expected on that site. Hence, a degraded forest delivers a reduced supply of goods and services from the given site and maintains only limited biological diversity. Biological diversity of degraded forests includes many non-tree components, which may dominate in the undercanopy vegetation.
Agro-forest An agro-forest is a complex of treed areas within an area that is broadly characterised as agricultural or as an agro-ecosystem.
Reforestation Reforestation is the re-growth of forests after a temporary (< 10 years.) condition with less than 10% canopy cover due to human-induced or natural perturbations (FAO, FRA 2000).
Afforestation Afforestation is the conversion from other land uses into forest, or the increase of canopy cover to the 10% defined threshold for forest (FAO, FRA 2000).
Forest fragmentation Forest fragmentation refers to any process that results in the conversion of formerly continuous forest into patches of forest separated by non-forested lands.
Habitat loss Habitat loss, used with reference to an individual species, is the permanent conversion of former (forest) habitat to an area where that species can no longer exist, be it still forested or not.
Forest species A forest species is a species that forms part of a forest ecosystems or is dependent on a forest for part or all of its day-to-day living requirements or for its reproductive requirements. Therefore, an animal species may be considered a forest species even if it does not live most of its life in a forest.
Native species A native species is one which naturally exists at a given location or in a particular ecosystem, i.e. it has not been moved there by humans.
Endemic species An endemic species is a native species restricted to a particular geographic region owing to factors such as isolation or in response to soil or climatic conditions.
Alien species An alien species is a species, sub-species or member of a lower taxon that has been introduced outside its normal past and present distribution; the definition includes the gametes, seeds, eggs, propagules or any other part of such species that might survive and subsequently reproduce (GISP, 2001).
Invasive alien species An invasive alien species is an alien species which becomes established in natural or semi-natural ecosystems or habitats. It is an agent of change and threatens native biological diversity (IUCN, 2000).

FAO Definitions

Taken from the Forest Resources Assessment 2000 main report (see the report's appendices for more terms and definitions).

Forest and related land use classifications


Terms Definitions
Forest Forest includes natural forests and forest plantations. It is used to refer to land with a tree canopy cover of more than 10 percent and area of more than 0.5 ha. Forests are determined both by the presence of trees and the absence of other predominant land uses. The trees should be able to reach a minimum height of 5 m. Young stands that have not yet but are expected to reach a crown density of 10 percent and tree height of 5 m are included under forest, as are temporarily unstocked areas. The term includes forests used for purposes of production, protection, multiple-use or conservation (i.e. forest in national parks, nature reserves and other protected areas), as well as forest stands on agricultural lands (e.g. windbreaks and shelterbelts of trees with a width of more than 20 m), and rubberwood plantations and cork oak stands. The term specifically excludes stands of trees established primarily for agricultural production, for example fruit tree plantations. It also excludes trees planted in agroforestry systems
Natural forest A forest composed of indigenous trees and not classified as forest plantation.
Forest plantation A forest established by planting or/and seeding in the process of afforestation or reforestation. It consists of introduced species or, in some cases, indigenous species.
Other wooded land Land that has either a crown cover (or equivalent stocking level) of 5 to10 percent of trees able to reach a height of 5 m at maturity; or a crown cover (or equivalent stocking level) of more than 10 percent of trees not able to reach a height of 5 m at maturity; or with shrub or bush cover of more than 10 percent.

Forest change processes


Terms Definitions
Afforestation Establishment of forest plantations on land that, until then, was not classified as forest. Implies a transformation from non-forest to forest.
Natural expansion of forest Expansion of forests through natural succession on land that, until then, was under another land use (e.g. forest succession on land previously used for agriculture). Implies a transformation from non-forest to forest.
Reforestation Establishment of forest plantations on temporarily unstocked lands that are considered as forest.
Natural regeneration on forest lands Natural succession of forest on temporarily unstocked lands that are considered as forest.
Deforestation The conversion of forest to another land use or the long-term reduction of the tree canopy cover below the minimum 10 percent threshold (see definition of forest and the following explanatory note).
Explanatory note: Deforestation implies the long-term or permanent loss of forest cover and implies transformation into another land use. Such a loss can only be caused and maintained by a continued human-induced or natural perturbation. Deforestation includes areas of forest converted to agriculture, pasture, water reservoirs and urban areas. The term specifically excludes areas where the trees have been removed as a result of harvesting or logging, and where the forest is expected to regenerate naturally or with the aid of silvicultural measures. Unless logging is followed by the clearing of the remaining logged-over forest for the introduction of alternative land uses, or the maintenance of the clearings through continued disturbance, forests commonly regenerate, although often to a different, secondary condition. In areas of shifting agriculture, forest, forest fallow and agricultural lands appear in a dynamic pattern where deforestation and the return of forest occur frequently in small patches. To simplify reporting of such areas, the net change over a larger area is typically used. Deforestation also includes areas where, for example, the impact of disturbance, overutilization or changing environmental conditions affects the forest to an extent that it cannot sustain a tree cover above the 10 percent threshold.
Forest degradation Changes within the forest which negatively affect the structure or function of the stand or site, and thereby lower the capacity to supply products and/or services.
Forest improvement Changes within the forest which positively affect the structure or function of the stand or site, and thereby increase the capacity to supply products and/or services.

WCMC / CIFOR Definitions

Taken from A Global Overview of Forest Conservation

Tropical forests


Terms Definitions
Mangroves Natural forests with > 30% canopy cover, composed of species of mangrove tree, generally along coasts in or near brackish or salt water.
Freshwater swamp forest Natural forests with > 30% canopy cover, below 1200m altitude, composed of trees with any mixture of leaf type and seasonality, but in which the predominant environmental characteristic is a waterlogged soil.
Lowland evergreen broadleaf rain forest Natural forests with > 30% canopy cover, below 1200m altitude that display little or no seasonality, the canopy being > 75% evergreen broadleaf.
Semi-evergreen moist broadleaf forest Natural forests with > 30% canopy cover, below 1200m altitude in which between 50-75% of the canopy is evergreen, > 75% are broadleaves, and the trees display seasonality of flowering and fruiting.
Deciduous/semi-deciduous broadleaf forest Natural forests with > 30% canopy cover, below 1200m altitude in which between 50-100% of the canopy is deciduous and broadleaves predominate (> 75% of canopy cover).
Sclerophyllous dry forest Natural forests with > 30% canopy cover, below 1200m altitude, in which the canopy is mainly composed of sclerophyllous broadleaves and is > 75% evergreen.
Thorn forest Natural forests with > 30% canopy cover, below 1200m altitude, in which the canopy is mainly composed of deciduous trees with thorns and succulent phanerophytes with thorns may be frequent.
Needleleaf forest Natural forest with > 30% canopy cover, below 1200m altitude, in which the canopy is predominantly (> 75%) needleleaf.
Mixed broadleaf/needleleaf forest Natural forests with >30% canopy cover, below 1200m altitude, in which the canopy is composed of a more or less even mixture of needleleaf and broadleaf crowns (between 50:50% and 25:75%).
Lower montane forest Natural forests with > 30% canopy cover, between 1200-1800m altitude, with any seasonality regime and leaf type mixture.
Upper montane forest Natural forests with > 30% canopy cover, above 1800m altitude, with any seasonality regime and leaf type mixture.
Sparse trees and parkland Natural forests in which the tree canopy cover is between 10-30%, such as in the savannah regions of the world. Trees of any type (e.g., needleleaf, broadleaf, palms).
Disturbed natural forest Any forest type above that has in its interior significant areas of disturbance by people, including clearing, felling for wood extraction, anthropogenic fires, road construction, etc.
Exotic species plantation Intensively managed forests with > 30% canopy cover, which have been planted by people with species not naturally occurring in that country.
Native species plantation Intensively managed forests with > 30% canopy cover, which have been planted by people with species that occur naturally in that country.

Non-tropical forests


Terms Definitions
Freshwater swamp forest Natural forests with > 30% canopy cover, composed of trees with any mixture of leaf type and seasonality, but in which the predominant environmental characteristic is a waterlogged soil.
Deciduous broadleaf forest Natural forests with > 30% canopy cover, in which > 75% of the canopy is deciduous and broadleaves predominate (> 75% of canopy cover).
Sclerophyllous dry forest Natural forest with > 30% canopy cover, in which the canopy is mainly composed of sclerophyllous broadleaves and is > 75% evergreen.
Evergreen needleleaf forest Natural forest with > 30% canopy cover, in which the canopy is predominantly (> 75%) needleleaf and evergreen.
Deciduous needleleaf forest Natural forests with > 30% canopy cover, in which the canopy is predominantly (> 75%) needleleaf and deciduous.
Mixed broadleaf/needleleaf forest Natural forest with > 30% canopy cover, in which the canopy is composed of a more or less even mixture of needleleaf and broadleaf crowns (between 50:50% and 25:75%).
Evergreen broadleaf forest Natural forests with > 30% canopy cover, the canopy being > 75% evergreen and broadleaf.
Sparse trees and parkland Natural forests in which the tree canopy cover is between 10-30%, such as in the steppe regions of the world. Trees of any type (e.g., needleleaf, broadleaf, palms).
Disturbed natural forest Any forest type above that has in its interior significant areas of disturbance by people, including clearing, felling for wood extraction, anthropogenic fires, road construction, etc.
Exotic species plantation Intensively managed forests with > 30% canopy cover, which have been planted by people with species not naturally occurring in that country.
Native species plantation Intensively managed forests with > 30% canopy cover, which have been planted by people with species that occur naturally in that country.

WRI Definition


Terms Definitions
Frontier forests Frontier forests are large, relatively intact forest ecosystems. A frontier forest must meet the following criteria:
  • It is primarily forested.
  • It is large enough to support viable populations of all species associated with that forest type even in the face of natural disasters of a magnitude to occur once in a century.
  • Its structure and composition are determined mainly by natural events, and it remains relatively unmanaged by humans, although limited human disturbance by traditional activities is acceptable.
  • In forests where patches of trees of different ages occur naturally, the landscape shows this type of heterogeneity.
  • It is dominated by indigenous tree species.
  • It is home to most, if not all, other plants and animals that typically live in this forest.

  • United Nations
  • United Nations Environment Programme