Governments, the general public and the international community at large have manifested increasing concern over the clearing and degradation of forests in many regions of 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 de Janeiro, June 1992) has amply reflected this unprecedented concern for the fate of the world's forests.

There cannot be sound decisions and actions, however, in the management of forests at any level, whether local or global, without reliable information on their condition and evolution over time. Such information is indispensable whatever the objective of management of forests, be it production of fuelwood or industrial wood for domestic use or export, conservation of biodiversity, mitigation of climate change at global level or multiple use. Thus, in Chapter 11 of UNCED Agenda 21 titled �Combating deforestation�, the assessment and systematic observations of forest resources is made 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 four components: (a) the assessment for the tropical countries; (b) the assessment of the forest resources of the industrialized countries carried out jointly by FAO and the Economic Commission for Europe of the United Nations; (c) the assessment for the non-tropical developing countries; and (d) the global synthesis.

Classifications and definitions used in national forest inventories often differ from one another, since they are designed to satisfy specific national or even local needs. To arrive at a common classification, format and reference date, original data provided by countries had to be reorganized. It must be stressed, however, that the standardized 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 global 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 the staff concerned with Forest Resources Assessment 1990.

This assessment is intended to satisfy many of the urgent information needs of policy makers, the scientific community and the general public. It has revealed, however, 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 of the world's forest resources a continuous and evolving programme.

David A. Harcharik

Assistant Director-General

Forestry Department