Jean-Paul Lanly is Director of the FAO Forest Resources Division.
During the Neolithic period, the earth was inhabited by a mere 80 million human beings, meaning a density of little more than one person for every 2 km² For millennia, the population of the world grew very slowly, reaching 450 million in 1650, when the pace of growth began to quicken; 750 million in 1750; 1 100 million in 1850; 2 500 million in 1950; and... 5 300 million in 1990: a density of more than 40 people per km²
The world's vegetation, especially the forests and other wooded formations, was progressively cleared or overexploited down through the ages. This onslaught would swell as agricultural and industrial civilizations flourished, with vegetation holding its own or even recovering only when populations were reduced by conflict or epidemics.
By the beginning of the twentieth century, deforestation had peaked in the developed world whereas, in the tropics and subtropics, the process of deforestation was still fairly limited. During the second half of this century, in the industrial countries in the temperate clime, forest plantations, reforestation and natural forest regeneration have more than made up for the forest land cleared for urbanization and infrastructure. This is a positive and upward trend, despite forest degradation from fire, acid rain and over-cutting. In the tropics, however, the pace of deforestation, accompanied by various processes of degradation (e.g. in the Mediterranean countries), has accelerated.
At the current point in time, practically all of the earth's forest land is in a dynamic state of instability. In this context, a continuously updated inventory of forests and their resources - or, to use the term adopted by the United Nations Conference on Environment and Development (UNCED) in Chapter 11 of Agenda 21, "systematic observations" of forests - is more imperative than ever before at every level, from local forest management units up to regional and global levels.
At the same time, the demand from governments, decision-makers and the public at large for information on forests and their resources has become increasingly exacting and pressing. Nor are the scientific community and the media less demanding, especially regarding information on the relationship between forests and global environmental issues such as climate change and the conservation of biodiversity. Their need for regional and global data sometimes exceeds what can be obtained at local and national levels, whether the information they need is thematic (for instance, species composition of ecosystems) or geographical (data are increasingly sought in map as well as statistical form).
Many people protest that we know more about the surface of the moon than we do about the plant cover of the earth. One could retort that, paradoxically, the absence of both plant and human life on the moon, and therefore of interaction between them, is precisely what makes mapping the moon so much easier. Other people are amazed that, despite all the lookout posts represented by high-resolution and meteorological satellites, we still have no worldwide "push-button" system for monitoring forest ecosystems.
Is it really necessary to remind people that things are not that simple? The increasingly refined and complex data that make up remote sensing's "ground truth" have to be gathered on-site, and this can be done on a permanent basis only by experts and institutions in the countries concerned, particularly by national forest inventory units which, in the vast majority of developing countries, either need strengthening or have yet to be created. The approach that should be followed is the one applied in the European region: here, under the aegis of FAO and the UN Economic Commission for Europe (ECE), basic data gathered by national institutions "flow" upwards to the regional level where they are compiled after inconsistencies have been removed and the necessary adjustments made at meetings among the national experts involved. At present, this bottom-up approach cannot be fully applied in the developing regions owing to the weakness of most of the relevant national institutions, hence a certain amount of top-down flow and centralization is still necessary.
Nonetheless, efforts must be made - as FAO has done and continues to do - to move towards a situation where global assessments can be based entirely on reliable, homogeneous statistical and map data supplied by national institutions. It is plain that this approach implies and should go hand in hand with the fortification of these institutions and the training of their researchers and technicians.
Whether we are talking about continuous assessment of forest resources or the development of appropriate national capabilities, UNCED's Agenda 21 charts a clear path. It is up to us to follow it. FAO, for its part, will continue to work in this direction and appeals to all member countries as well as the donor community to join forces in this important endeavour.