Convention on biological diversity

USE OF TERMS

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.

A biome is the broadest forest classification unit. 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.

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.

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 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.

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 [Is this clear enough?]. 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.

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 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.

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. [Possible addition: Depending on the intensity of management, species mix, presence of understorey vegetation and natural species regeneration within the planted forest, and proximity to natural forest stands or seed sources, the planted forest may support, to a lesser or greater extent, local biological diversity ]

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.

An agro-forest is a complex of treed areas within an area that is broadly characterised as agricultural or as an agro-ecosystem.

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 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 refers to any process that results in the conversion of formerly continuous forest into patches of forest separated by non-forested lands.

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.

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.

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.

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.

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).

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).