For the definition of forest, FRA 2000 adopted a threshold of 10 percent minimum crown cover. The definition includes both natural forests and forest plantations. It excludes stands of trees established primarily for agricultural production (e.g. fruit tree plantations).

Based on the consensus recommendation of the Intergovernmental Panel on Forests (IPF) in 1997, this same definition was used for all countries in FRA 2000. In FRA 1980 and FRA 1990, the 10 percent threshold was used for developing countries, but for the industrialized countries a threshold of 20 percent was used.

Using the FRA 2000 global definition of forests and new baseline information, it was estimated that the world¿s forest cover at the year 2000 was about 3.9 billion hectares, or approximately 0.6 ha per capita. About 95 percent of the forest cover was in natural forest and 5 percent in forest plantations. Using a combination of new global maps and statistical data, FRA 2000 also estimated the distribution of forest area by ecological zones: 47 percent is in the tropics, 33 percent in the boreal zone, 11 percent in temperate areas and 9 percent in the subtropics.

The uniform application of one forest definition had a significant impact on the global findings for the year 2000. The estimated forest area was 400 million hectares greater than the corresponding global figure reported for 1995; the change in definition particularly influenced the forest area estimates for Australia and the Russian Federation, where large areas of forest have between 10 and 20 percent canopy cover.

Another factor leading to the upward revision of forest cover since FRA 1990 was improved information from more recent national inventories which generated higher area estimates for forests in some countries. In other cases, more detailed breakdown of forest classes in the inventory reports facilitated an improved classification of national results into FRA 2000 global standards.

The major components of forest area change are categorized as deforestation, afforestation and natural expansion of forests into previously non-forested areas.

Deforestation is the conversion of forest to another land use or the long-term reduction of the tree canopy cover below the minimum 10 percent threshold.

Afforestation is the establishment of forest plantations in areas not previously in forest, and denotes a change from non-forest to forest. It differs from reforestation, which is the establishment of forests (through planting, seeding or other means) after a temporary loss of the forest cover. Areas under reforestation are classified as forest since the forest is actively regenerating.

Natural expansion of forests refers to the expansion of forest through natural succession on to previously non-forested lands, usually abandoned farmland.

After adjustment of the 1990 forest area to the same definition and baseline information used for FRA 2000, the net global change in total forests was calculated as the sum of deforestation (a negative change) and the gain in forest cover due to the establishment of forest plantations (afforestation) and natural expansion of forests on previously unforested lands.

Deforestation in the 1990s was estimated at 14.6 million hectares per year. The figure represents the balance of annual losses of natural forests (estimated at 16.1 million hectares per year or 0.42 percent per year) minus the area of natural forest that was replaced through reforestation with forest plantations (1.5 million hectares per year), since plantations are considered as a type of forest.

Expressed in another way, during the 1990s the world lost 4.2 percent of its natural forests, but it gained 1.8 percent through reforestation (with plantations), afforestation, and the natural expansion of forests, resulting in a net reduction of 2.4 percent over the ten-year period.

The worldwide gain in forest cover totalled 5.2 million hectares per year, the aggregate of afforestation (1.6 million hectares per year) and natural expansion of forests (3.6 million hectares per year).

Thus the net global change in forest area between 1990 and 2000 was estimated as -9.4 million hectares per year: the sum of -14.6 million hectares of deforestation and 5.2 million hectares of gain in forest cover. The global change (-0.22 percent per year) represents an area about the size of Portugal. The estimated net loss of forests for the 1990s as a whole was 94 million hectares - an area larger than Venezuela.

In addition to the analysis of statistical data from countries, which provided the core information, FRA 2000 included a pan-tropical remote sensing based statistical survey which covered 87 percent of the forests in tropical developing countries. This study provided the first consistent methodology for assessing forest change between two assessment periods. The remote sensing survey revealed that the deforestation process in the tropics is dominated by direct conversions of forest to agriculture. Statistical results from the study showed a slight decrease in the rate of forest loss, from 9.2 million hectares per year in the 1980s to 8.6 million hectares per year in the 1990s. However, this difference fell within the margin of error for the estimates.

Statistics from the country studies showed a similar pattern to those of the remote sensing survey, with slight reductions in overall net forest loss between the 1980s and 1990s. Overall, however, the loss of natural forests is still high in the tropics, and increases in plantation establishment and the natural expansion of forests have not been compensating for the losses incurred.