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Results of the assessment



Source data as well as data in various stages of processing are stored in FAO's FORIS database. This database is an important output of the assessment process and marks the starting point of tropical forest resources assessment on a continuing basis. Using the database, it is possible to make a study of historical trends and future prospects. As more multi-date observations become available and are added to the database, the precision of estimates, particularly of change rates, is expected to increase.

State of forest area and rate of change

As described in the methodology (Annex 2), the estimations of forest area and changes have been made at subnational level. Results are then aggregated at national level for reporting purposes. The national estimates are further aggregated at subregional, regional and global tropical levels as presented in tables in the Annex.

It is important to note the distinction between forest and plantation made in the assessment of developing countries. While the term �forest� refers to a formation of natural origin, �plantation� implies an artificially established crop involving the replacement of the indigenous species by a new and essentially different species or genetic variety (see Annex 2.3: Definitions).

Tropical Regions

The forest area in the tropical regions was 1 756 million ha at end-1990 compared with 1 910 million ha at end-1980. Thus, the average annual deforestation during the past decade amounts to 15.4 million ha, a compound annual rate of deforestation of 0.8 per cent. The largest extent of forest area was in Latin America and the Caribbean (918 million ha; 52 per cent of the total tropical forest area), followed by Africa (528 million ha; 30 per cent), and Asia and Pacific (311 million ha; 18 per cent). The annual loss of forest area by region was: Latin America and the Caribbean 7.4 million ha (0.8 per cent), Africa 4.1 million ha (0.7 per cent), and Asia and Pacific 3.9 million ha (1.2 per cent) as given in Annex 1 : table 4.

Among the subregions, the following have relatively high rates of deforestation: East Sahelian and West Africa, Tropical South Africa; Continental and Insular Asia; Central America and Mexico.

Non-tropical Regions

The estimated forest area at end 1990 was 180 million ha (6.4% of land); in addition there were 111 million ha (4% of land) of other natural woody vegetation (mainly shrubs).

The more forested sub-regions are South America (11.6 % of land) and Temperate Asia (10.6 %). In North Africa and Middle East the present natural forest cover is less than 1 %.

In absolute term the bulk of natural forests are located in Asia (mainly in China. The second important sub-region is South America, as shown in the Annex 1 table 4.

The estimated annual loss of natural forest cover was 0.85 million ha (0.5 percent) which is lower than the deforestation rate estimated for tropical countries (0.8 percent).

Comparison with the 1980 Assessment (in table 13).

It is of interest to compare the forest area estimates for the base year 1980 made by the two FAO assessments of 1980 and 1990.

The current estimate of the 1990 forest cover is 2 105 million ha against the earlier figure of 2 125 million ha, i.e. about 20 million ha less. The area of forest and other wooded lands is now estimated at 3 117 million ha against the earlier figure of 3 267 million ha, i.e. 150 million ha less. These changes in the baseline figures illustrate the problem involved in comparing the estimates of deforestation in successive rounds of assessment.

Differences in the estimates of the 1980 forest cover between the two assessments arise mainly from two factors: the increased amount of information in the 1990 assessment relating to 1980 and following years; and the improved procedures for updating estimates at different years employed in the more recent assessment.

State of forest biomass and assessment of change

Country estimates are given in annex 1, table 5, and a summary in table 14. The Caribbean, Central Africa and Insular South East Asia subregions have still more than 200 tons of biomass per hectare on average, whilst the lowest values are found in tropical Southern Africa and in Sahelian Africa. It may also be noticed that the biomass per caput values are extremely low in South Asia due to very high population pressure. Low values are also found in West Africa, Sahelian Africa and Central America. It is remarkable that the average biomass per caput of Asia is only one fourth that of Africa and less than one tenth that of Latin America and the Caribbean.

Annual loss of biomass is estimated at slightly over 2 500 million tons, of which more than 50 per cent is contributed by the Latin American region, nearly 30 per cent by tropical Asia and about 20 per cent by tropical Africa.

The average biomass density in the non-tropical developing regions is estimated to be 170 tons/ha, and the annual loss to be 152 millions of tons corresponding to 0.9 millions of hectares of annual deforestation.

The state of Forest Ecosystem

The report on the state of forest ecosystems, as presented in this section, is an important element of assessment of biological diversity. Combined with data on species richness, the estimate of area losses by ecosystem can be used to make indicative estimates of the risk of loss of species richness.

For the present reporting, the ecofloristic zones were grouped into broad forest formations: one upland and three lowland for the tropics and only one formation for the non-tropics. (see Table 15)

At end 1990 tropical lowland formations covered 1 544 million ha (88 percent of the total tropical forest area) and upland (hill and montane) formations 204 million ha (12 percent). Among the lowland formations, the tropical rainforests constituted the largest portion, namely 718 million ha (or 41 percent), the moist deciduous forests 587 million ha (33 percent) and the dry and very dry zone forests 238 million ha (14 percent). The rest of the forests, nearly 8 million ha, were scattered in the non-forest zone.

The annual losses of forest cover by ecological zone in the tropics were: the tropical rainforests 4.6 million ha (0.6 percent), the moist deciduous forests 6.1 million ha (1.0 percent), the dry and very dry zone forests 2.2 million ha (0.9 percent) and the upland formations 2.5 million ha (1.1 percent).

Forest formations in the non-tropical regions of the developing world are very much reduced in area due to deforestation over many centuries.

The whole region extending from the Mediterranean Basin to Indus valley has been subject to intense human activity dating back to 3000 BC. Since that time several great civilizations such as Egyptian, Indian, Babylonian, Greek and Roman, all with a regional sway of power, have risen and fallen. All of them made extensive use of forest lands for human settlement and agriculture, grazing by domestic animals; and use of wood in housing, transport, mining and metallurgy. The process has been going on for several thousands of years in a essentially forest poor region.

Similar events also took place in China. The regions in the northern and northwestern China along the Yellow River, where the Chinese first settled, were once extensively wooded. There were boundless stretches of "tsao mu" (grass and forest) everywhere. After more than 5 500 years of over-utilization action the forests of China today are instead quite reduced.

The historical processes differ in South America, where the massive clear-cut of forest for agriculture purposes dates only few centuries and the demand for new land for agriculture and especially pasture is still active, with the agricultural frontier still expanding.

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