User:Matej Sch/sandbox



Although forest is a term of common parlance, it is not easy to define it precisely for practical purposes. There are more than 800 definitions (mostly the national ones) of forest used around the world for different purposes at different scales. Forest is commonly understood as an area with a high density of trees or a biological community dominated by trees, however, for practical purposes (legislation, forest inventories, etc) it is necessary to make the definition broad enough to include developmental stages of forests, whether natural or resulting from a management intended to continue using the area as a forest. Other definitional issues include specifics of some forest types, national specifics (legislation, traditions), definition of minimum forest area, etc.

There are three broad categories of forest definitions in use: administrative, land use, and land cover. Land Use definitions are based upon the primary purpose that the land actually serves (e.g. as forest land, agriculture land, etc). They usually include also areas covered by young trees not reaching the threshold, clearcut (but not permanently deforested) areas or treeless areas resulting from natural disasters, forest roads, cleared boundary lines, etc. Administrative definitions primarily define forest or forest land from the viewpoint of national legislations and, usually, declare the intent to retain this defined land as a permanent forest with low probability to be converted to other land use. Besides the above-mentioned treeless areas, these definitions can, in some countries, also include some non-forest ecosystems scattered within forests, such as alpine grasslands, peatlands, etc. On the other hand, areas newly afforested via natural expansion of forest may not be included (deforestation, if allowed, should be solved by the respective procedure immidiately). Forest area based on these definition, therefore, might be be not identical to a real actual forest area. Nevertheless, many national statistics are based on such definitions, as no other data are available and, in majority of countries, the differences are reasonable. Land Cover definitions define forests on the basis of vegetation characteristics. Forests are usually characterised by a percentage of crown cover (canopy density) and a minimum height of trees that are taken into account. These definitions, unlike the above mentioned, may exclude stands of young trees or temporarily treeless that are regenerating after harvest or natural disturbance. Under land use definitions, there is considerable variation on where the cutoff points are between a forest, woodland, and savanna. Under some definitions, forest is defined by rather high levels of tree canopy cover, from 60% to 100%, excluding savannas and woodlands in which trees have a lower canopy cover. Other definitions consider savannas to be a type of forest, and include all areas with tree canopies over 10%. Some of important definitions combine above-mentioned approaches.

FAO (for Global Forest Resources Assessment purposes) defines forest by the presence of trees as well as by the absence of other predominant land uses : [Forest is] "land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover  of more than 10 percent, or trees able to reach these thresholds in situ. It does not include land that is predominantly under agricultural or urban land use".''

with explanatory notes saying that the definition includes :
 * areas with young trees not reaching the above-mentioned standard but expected to reach it in the near future.
 * areas temporarily unstocked due to clear-cutting as part of a forest management practice or natural disasters, which are expected to regenerate within 5 years;
 * forest roads, firebreaks and other small open areas;
 * windbreaks, shelterbelts and corridors of trees with an area of more than 0.5 hectares and width of more than 20 meters;
 * abandoned agricultural land overgrown with trees that have, or are expected to reach above-mentioned standard;
 * mangroves in tidal zones, regardless whether their area is classified as land area or not;
 * rubberwood, cork oak and Christmas tree plantations;
 * areas with bamboo and palms provided that land use, height and canopy cover criteria are met;

and excludes:
 * tree stands in agricultural production systems, such as fruit tree plantations, oil palm plantations, olive orchards and agroforestry systems when crops are grown under tree cover.