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Governments, the general public and the international community at, large have manifested increasing uneasiness over the clearing and degradation of forests all over the world. By devoting a significant part of its debate and decisions to issues of forest conservation and development, the United Nations Conference on Environment and Development (UNCED, Rio, June 1992) has amply reflected this unprecedented concern for the fate of the world's forests.

However there cannot be sound decisions and action in the management of forests at any level, whether local or global, without reliable information on their situation and evolution over time. Such information is indispensable whatever the objective of management of forests, be it fuelwood production at local level, timber production for export, conservation of biodiversity or mitigation of climate change at global level. Thus in Chapter 11 of UNCED Agenda 21 titled “Combatting deforestation”, the assessment and systematic observation of forest resources is a key element in one of the four programme areas.

In pursuance of its mandate, FAO has undertaken periodic assessments of the world's forest resources, of which the first was nearly 50 years ago in 1946 and the last in 1980. The 1990 Global Forest Resources Assessment builds upon the 1980 study. It has three components: (a) the assessment for the tropical countries which is presented in this report; (b) the assessment of the forest resources of the industrialised countries which has been carried out and published recently jointly by FAO and the Economic Commission for Europe of the United Nations; and (c) the assessment for the non-tropical developing countries which is to be published in early 1994.

This report provides comprehensive information on the current state of tropical forests including deforestation, management, conservation and development of the resource. It addresses for the first time issues related to forest degradation, loss of biomass and biodiversity. New methodology has been developed for more accurate estimation of changes. The core of this methodology is the ability to analyse forest resource data in the form of time series. Both data which were available with member countries and new data obtained from satellite remote sensing images have been used for this purpose.

Classifications and definitions used in forest inventories often differ from country to country, since they are designed to satisfy specific national or local needs. To arrive at a common classification, format and reference date, original data provided by countries had to be reorganised. It must be stressed, however, that the standardised country results in this international report are intended only to secure a consistent global picture; they do not replace the original country statistics which will remain a unique source of reference.

The 1990 assessment has been a key activity under the FAO Regular Programme, carried out with substantial support from donor countries. Its implementation has benefited greatly from ready cooperation of all countries which are reported upon here, as well as the technical contributions made by many scientific institutions and individuals. This report also reflects the dedication of Forest Resources Assessment 1990 Project staff.

This assessment is intended to satisfy most of the urgent information needs of policy makers, the scientific community and the general public. However, the exercise has revealed a need to fill certain gaps in knowledge and to improve national capacities to carry out their own forest resources assessments. FAO intends to give greater attention to these aspects in future and to make the assessment a continuous and adaptable process.

 C.H. Murray
Assistant Director-General
Forestry Department


The Forest Resources Assessment 1990 was supported by the Governments of Finland, France, Italy, the Netherlands, Sweden and Switzerland through a multi-donor trust fund. Major in-kind contributions were made by the Swedish University of Agricultural Sciences, the United States Forest Service and the World Conservation Monitoring Centre (Cambridge, United Kingdom). Personnel assistance was given through the Associate Professional Officers scheme of the Governments of Belgium, Germany, the Netherlands, Sweden and the United States of America. Member countries have contributed by sending source information, by cooperating in the interpretation of remote sensing data and by reviewing the compilations made by FAO. The assessment was conducted by a project team coordinated by Dr. K.D. Singh at FAO, Rome. The Food and Agriculture Organization is greatly indebted to all those who assisted in the implementation of the project by providing information, advice, facilities and funds.


AVHRRAdvanced Very High Resolution Radiometer
BIBLIOBibliography Documentation Programme
ECEEconomic Commission for Europe
ECREdge/core Ratio
EFZEcofloristic Zone
FAOFood and Agriculture Organization of the United Nations
FINNIDAFinnish International Development Authority
FORIS 1990Forest Resources Information System 1990
FRA 1990Forest Resources Assessment 1990 Project
GISGeographic Information System(s)
IBAMAInstituto Brasileiro do Meio Ambiente y dos Recursos Naturais Renovaveis (Brazil)
IGADDIntergovernmental Authority on Drought and Development
INPEInstituto Nacional de Pesquisas Espaciais (Brazil)
ITTOInternational Tropical Timber Organization
IUCNInternational Union for the Conservation of Nature (The World Conservation Union)
LANDSAT MSS/TMLANDSAT Satellite Multi-spectral Scanner/Thematic Mapper
NASANational Aeronautics and Space Administration (United States of America)
NOAANational Oceanic and Atmospheric Administration
PAIPerimeter Area Index
PCPersonal Computer
TCDCTechnical Cooperation among Developing Countries
TFAPTropical Forests Action Programme
UNCEDUnited Nations Conference on Environment and Development (Rio de Janeiro, Brazil, June 1992)
UNDPUnited Nations Development Programme
UNEP-GRIDUnited Nations Environment Programme - Global Resources Information Database
USDAUnited States Department of Agriculture
USGS/EROSUnited States Geological Survey/Earth Resources Observation Satellite
WCMCWorld Conservation Monitoring Centre


The main objectives of the present assessment were: (i) to provide reliable and globally consistent information on the state of the tropical forests by 1990 and the rates of change during 1981 to 1990 and (ii) to undertake studies on the process of deforestation and forest degradation and their environmental implications.

The assessment covering 90 countries was carried out in two phases. The available statistical information on forest cover area, growing stock, management, conservation and utilisation of forests was first compiled and incorporated into a database. The spatial information on vegetation cover, ecological zones and administrative boundaries at subnational level was scanned, edited and integrated with the statistical data in the form of a geographic information system. The collected data were used to build a deforestation model, to estimate forest cover area at end 1990 and rates of change during 1981 to 1990.

In addition, a remote sensing based survey of the tropical forests using high resolution satellite data of two dates, one close to 1980 and the other close to 1990, was implemented at 117 sample locations. State and change information was interpreted and stored in the form of change matrices following the standard procedure developed. These data were analysed to obtain in-depth knowledge of the process of deforestation and forest degradation on the sample locations, by geographic subregion and ecological zone. Results for Africa are presented as an example.

The pan-tropical forest cover was 1,756 million ha at end 1990 and 1,910 million ha at end 1980 (this latter figure replaces the earlier estimate of 1,935 million ha provided by the 1980 FAO/UNEP Tropical Forest Resources Assessment project). Thus, average annual deforestation during the past decade amounts to 15.4 million ha (0.8 percent in compound annual rate of deforestation). The largest extent of forest cover was in Latin America and Caribbean (918 million ha: 52 percent of the total tropical forest area), followed by Africa (528 million ha: 30 percent), and Asia and Pacific (311 million ha: 18 percent). The annual loss of forest cover by region was: Latin America and Caribbean 7.4 million ha (0.8 percent), Asia and Pacific 3.9 million ha (1.2 percent) and Africa 4.1 million ha (0.7 percent).

At end 1990 lowland formations were 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 biggest 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 loss of forest cover by ecological zone 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).

Comparing the forest area to the land area ratio for each ecological zone, it appears that 76 percent of the tropical rainforest zone is still covered with forest. As can be expected, the percentage of the forest cover declines with drier conditions and differences are quite obvious: 46 percent are forested in the moist deciduous, 30 percent in the dry deciduous and 19 percent for the dry and very dry zones together. One can assume that in the very dry zone the original forest area was considerably less than 100 percent of the total land area. This is in contrast to the rainforest and moist zones where the original forest area was close to 100 percent.

During 1961 to 1990 a steadily rising trend was observed regarding the area harvested for production of non-coniferous industrial roundwood in all three tropical regions, but little progress seems to have been made in the sustainable management of the natural forests.

The assessment results also indicate that 14 percent of the land area is set apart in the tropical zone for conservation purposes of which 3.8 percent is under total protection

The reported area of forest plantations in the tropics at end 1990 was 43.9 million ha and the net area (after deduction of mortality and failures) 30.7 million ha (namely 70 percent). During 1981 to 1990 the reported forest plantations area increased annually on average by 2.6 million ha and the net area by 1.8 million ha. Thus, the net area planted per annum was about 12 percent of the area deforested every year.

The special studies made by the Project show that forest fragmentation, biomass and biodiversity loss are important processes associated with deforestation and forest degradation in the tropics.

The work has clearly revealed that a great majority of the tropical countries have insufficient institutional capacity to collect and analyse data on a continuous basis. This finding has been highlighted by UNCED and confirms the need to include “establishing and/or strengthening capacities for the planning, assessment and systematic observation of forests” as a fully fledged programme area in Agenda 21.

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