Forest Resources Assessment WP 25

Field documentation of forest cover changes for the Global Forest Resources Assessment 2000

Rome, 2000

The Forest Resources Assessment Programme

Forests are crucial for the well-being of humanity. They provide foundations for life on earth through ecological functions, by regulating the climate and water resources, and by serving as habitats for plants and animals. Forests also furnish a wide range of essential goods such as wood, food, fodder and medicines, in addition to opportunities for recreation, spiritual renewal and other services.

Today, forests are under pressure from expanding human populations, which frequently leads to the conversion or degradation of forests into unsustainable forms of land use. When forests are lost or severely degraded, their capacity to function as regulators of the environment is also lost, increasing flood and erosion hazards, reducing soil fertility, and contributing to the loss of plant and animal life. As a result, the sustainable provision of goods and services from forests is jeopardized.

FAO, at the request of the member nations and the world community, regularly monitors the world’s forests through the Forest Resources Assessment Programme. The next report, the Global Forest Resources Assessment 2000 (FRA 2000), will review the forest situation by the end of the millennium. FRA 2000 will include country-level information based on existing forest inventory data, regional investigations of land-cover change processes, and a number of global studies focusing on the interaction between people and forests. The FRA 2000 report will be made public and distributed on the world wide web in the year 2000.

The Forest Resources Assessment Programme is organized under the Forest Resources Division (FOR) at FAO headquarters in Rome. Contact persons are:

Robert Davis FRA Programme Coordinator [email protected]

Peter Holmgren FRA Project Director [email protected]

or use the e-mail address: [email protected]


The Forest Resources Assessment (FRA) Working Paper Series is designed to reflect the activities and progress of the FRA Programme of FAO. Working Papers are not authoritative information sources – they do not reflect the official position of FAO and should not be used for official purposes. Please refer to the FAO forestry website ( ) for access to official information.

The FRA Working Paper Series provides an important forum for the rapid release of preliminary FRA 2000 findings needed for validation and to facilitate the final development of an official quality-controlled FRA 2000 information set. Should users find any errors in the documents or have comments for improving their quality they should contact either Robert Davis or Peter Holmgren at [email protected].

Paper drafted by: Alice M. Ennals, Ingemar Eriksson and Soren Dalsgaard
Editorial assistance: Patrizia Pugliese
Photos taken by: Ennals and Eriksson



Diameter of tree at breast-height (1.3 m above ground level)


Food and Agricultural Organization of the United Nations


Forest Resources Information System


Forest Resources Assessment


Geographical Information System


Global Positioning System


Non Governmental Organization


Regional Community Forestry Training Centre


Royal Forest Department


Remote Sensing Survey

T2, T3

Satellite images with acquisition date 1991 respectively 1998, used in the remote sensing study and covering the study areas.


Unit for area measurement (40m x 40 m, 1 ha = 6.25 rai)


Currency of Thailand, May 2000 (37 Bath = 1 USD)


In the Remote Sensing Survey, the term fallow is used for land where shifting cultivation is the dominating land use.

Change polygon

An area where the RSS land cover class has changed between the acquisition dates of T2 and T3.

Shifting cultivation

A traditional method of agriculture characterized by the rotation of fields rather than crops, the use of short cropping periods and long fallow periods, and the maintenance of fertility by allowing natural vegetation to regenerate on fallow land. Clearing of new or previously cropped land is often accomplished by cutting and burning vegetation. Also known as slash-and-burn or swidden agriculture.




1 Introduction
1.1 Objectives

2 Methodology
2.1 Preparations
2.2 Field measurements and observations
2.3 Photo documentation
2.4 Qualitative Data; Group discussions and transect walks

3 Findings
3.1 Literature overview
3.2 Study area 1

3.3 Study area 2 3.4 Study area 3

4 Experiences on practical issues
4.1 Preparations and logistics
4.2 Technical equipment
4.3 Approaching stake-holders

5 Methodological findings

6 What can be assessed?


FRA Working Papers

Top Of Page