Jean-Paul Lanly is with the Regional Council of Rural Engineering for Water and Forests, Ministry of Agriculture, Fisheries and Food, Paris.
An adaptation of the position paper for the Eleventh World Forestry Congress, "Forestry and woodland resources ".
Measuring the biomass of conifers in Cape Verde
At first sight, this area of the Congress's programme may appear fairly heterogeneous. It is, in fact, the only topic that groups together two of the more or less universally recognized main principles of sustainable forest management: assessing the importance of resources and the health and survival of forest ecosystems; the other areas each deal with only one, or part of one, of the other five principles: conservation of biological diversity, protection role, production factors, the socio-economic contribution of forestry and methods of sustainable forest management. Nevertheless, these two principles, and the six topics of this area in general, are quantitatively and qualitatively related to the state of forests and forest links to other soil-based activities. This article therefore evaluates and offers conclusions on the state of forests and trees and the biotic and abiotic threats they face (including the impacts of climatic changes), as well as their integration or competition with the other two main land uses, namely agriculture and urban expansion.
This article has two main sections: the first section, The current situation, outlines the situation and current trends within the six areas and presents some of the problems and questions that arise; the second section, Elements of response, identifies potential solutions for forestry agents to implement in their respective research and action programmes. These recommendations could be used to reinforce actions that have already been planned or initiated, to encourage a shift in existing policies and programmes, or to define new priorities.
The article's contents derive mainly from the various specialist articles available at the time of its preparation as well as from voluntary contributions on the six topics covered. FAO's excellent report, State of the world's forests 1997 (FAO, 1997a) has also been helpful, especially for the themes developed in the first section. Various other documents, in particular those prepared for or by the Intergovernmental Group on Forests of the Sustainable Development Commission, have been equally useful. Finally, specialist articles on other topics of the Congress have also been consulted.
The use of computer tools In forest assessement is of increasing importance. In the photo: forest workers consult computer database in S. Felice, Cape Verde
The present state of forest conservation and development
World public opinion certainly seems to be more aware of the state of trees and forests than ever before, at least since the start of the agricultural revolution. This concern varies in form and depth among the different countries, communities and individuals involved, depending on which goods and services are considered a priority. This heightened public interest explains the intensity of the debate on forest use and conservation at the local, national and international levels, and the greater attention decision-makers give to forests than in the past, not only verbally but also through actions such as the adoption of institutional and financial measures and resources.
At the same time, a constantly growing population means that demand for forest goods and resources has never been so high. Developing countries need forest land for agriculture as well as wood and other forest products; in addition to forest products, citizens in richer countries are making greater demands on forests for recreation, pleasure, scenery and conservation of biological diversity (this last demand applies to forests the world over). Furthermore, people everywhere are more and more dissatisfied with an increasingly artificial environment, and long for a world that is closer to nature, leading them to question certain forms of intensive forestry such as rapid-growth, single-species plantations.
Another important factor at present is the emphasis given to private initiatives and the privatization of forest management (or management of forestry lands) as well as to the systematic reduction of public spending. The consequences of this on medium- and long-term forestry policies and related measures cannot be predicted, but it must be borne in mind that it is difficult to reconcile this emphasis with the maintenance of forest multiple use, the importance given to forests' non-market resources, and the obligatory long-term character of forest management in general.
The state of the world's forests
In 1995, it was estimated that (natural, "semi-natural" and planted) forests covered an area of 3.454 billion ha, that is some 26.6 percent of the total land mass (excluding Greenland and Antarctica); in 1990, other "wooded areas" (areas of bush, scrubland, heath, fallow land, etc.) covered an additional 1.68 billion ha. About 57 percent of the world's forests ( 1.961 billion ha) were in developing countries where the proportion of forest cover was the same as in the developed world (with 1.493 billion ha of forest) and therefore the same worldwide. Forests in temperate and boreal regions were a little less extensive (48.5 percent of the total land mass) than those of the humid and dry tropics. More than two-thirds of the world's forests were in seven countries: the Russian Federation, Brazil, Canada, the United States, China, Indonesia and former Zaire, in descending order. In 29 countries (including 21 tropical countries), more than half the land was covered by forest; while the proportion given over to forestry was less than 10 percent in 49 other countries (mainly small, unwooded, island states and territories) and in several entire subregions, including Saharan Africa (7.5 percent), non-tropical southern Africa (6. 8 percent), the Near East ( 1.9 percent) and North Africa ( 1.2 percent).
Natural forests cover a negligible area in Europe, significant areas in the rest of the developed world and the majority of the humid tropical countries (dense forests). These are forests which have not been used for production or silviculture (unlike the so-called "semi-natural" forests) and which are generally characterized by a complex structure, a range and allocation of species that are unique to the site, a wide range of ages and the presence of dead or dying trees.
Although it is often difficult to distinguish plantations from other forests in the developed world, they cover an estimated total of about 80 million to 100 million ha. In 1995, their estimated total area in developing countries was about 81 million ha, more than 80 percent of which were in the Asia and the Pacific region and more than 40 percent in China alone (which was followed in importance by India, Indonesia, Brazil, Viet Nam, the Republic of Korea and Chile, each with more than I million ha of plantation). In tropical countries as a whole, the proportion of large industrial plantations has decreased in favour of afforestation at village, farm and agroforestry levels, especially in the Asia and Pacific region (some of this new forestry supplies the industrial wood markets); three genera (eucalyptus, pines and acacias) and one species (teak) account for about half of all plantations. To complete the list of trees that are planted, "non-forestry" plantations should also be mentioned; these include rubber plants, oil- and coconut palms in tropical countries, as well as the trees used along hedgerows, the sides of roads and in urban gardens. Although these trees are only partially registered or not registered at all, they contribute (to a greater or lesser extent, depending on the country) to the production of forest goods and resources.
From 1990 to 1995, the area covered by forests (including plantations) in industrialized countries (excluding the Russian Federation) increased annually by about 1.75 million ha ( 0.39 million ha were in Europe and 0.76 million in North America). At the same time the area covered by natural or semi-natural forests in developing countries decreased every year by 13.7 million ha (12.9 million ha of which were in the tropics). This reduction was partly compensated by the 0.7 million ha planted every year (0.3 million ha in tropical countries), but the net annual reduction in forests was still 13 million ha. Every year during this period, the earth lost a total of 56.3 million ha of forest (equivalent to an area the size of France), that is 0.33 percent of total forest cover (or I percent every three years), with the annual loss in developing countries being 0.65 percent.
The FAO study on changes to tropical forest stands in the 1980s (FAO, 1996) has made it easier to identify the deforestation processes and factors in that part of the world. For example, the study showed that 40 percent of the dense tropical forest converted to other uses was completely cleared, mainly for agriculture and animal breeding, 10 percent was partially cleared or "fragmented" for the same reasons, 26 percent was transformed into bush for nomadic agriculture with short fallow periods, 20 percent transformed into light or mosaic forest for nomadic agriculture with long fallow periods, and 4 percent was converted into agricultural or forestry plantations. It is obvious that the various forms of agriculture - permanent with annual crops or perennial plantations. or nomadic with long or short periods of fallow - are the main deforestation factors in tropical countries, where most deforestation in developing countries takes place ( 12.9 million of the total 13.7 million ha deforested each year). The interaction of forests and agriculture is at the heart of the deforestation problem and preliminary solutions lie in finding a better way of integrating conservation and forest exploitation in rural development.
Conversion of forest land to agriculture In Japan
If we consider the state of forest health or deterioration rather than the reduction (or increase) in land occupied by forest ecosystems, the situation remains equally full of contrasts. Although total forest areas in industrialized countries are gradually increasing, the causes of deterioration and threats to forest health remain. Thus, although emissions of sulphur and nitrogen oxide have decreased in Europe in recent years, forest degradation continues unabated despite improvements in some places.
Elsewhere, the total area destroyed by forest fire seems to have decreased slightly in the industrialized world as a whole (where more than 4 million ha of forest and other wooded areas were burnt down in the early 1990s) thanks to general improvements in methods of prevention, detection and control; nevertheless, although smaller areas are concerned, fire outbreaks have become more frequent. In addition, diseases (such as those of elms and plane trees) and insect infestations continue to be threats, often made worse by restricted genetic variation among trees.
The nature of forest degradation in the developing world and the factors involved very across different regions and ecological zones. The mixed forestry and grasslands of dry tropical and subtropical areas are subject to three main types of destruction: repeated bush fires, which are particularly damaging if they take place at the height of the dry season; overgrazing; and overexploitation for fuelwood and charcoal. Despite the unfavourable climatic conditions in the humid tropics, forest fires constitute a threat that can be occasional (as in mixed evergreen forests) or, in other cases, recurrent (as in natural pine forests or plantations). Another source of degradation is the exploitation of timber without regard for the preservation of the ecosystem and without management plans, particularly in forests rich in commercial species. 'In addition, disease and insects can have a particularly damaging impact on plantations, and certain insect pests, such as the lead bee psyllid and the cypress aphid, have been advancing rapidly out of their native regions in recent years. Finally, scattered species and populations have been affected by various other causes of decline, caused by atmospheric pollution and other factors.
The evolution of forestry information requirements
It may seem obvious that the objectives of forest resource assessment and surveillance programmes and their information should match the requirements of potential users. Nevertheless, assessments continue to be based on available resources rather than on objectives that have been clearly defined in advance. The importance of including surveys in planning and decision-making processes cannot be overemphasized.
Controlled fire can be a useful part of forest management. In the photo: controlled fire as a hunting technique in the Central African Republic
This necessity is all the less difficult to fulfil since forestry surveys are carried out at restricted and localized geographical and decision-making levels; hence the officials are closer to the end users. The same is true at higher levels, particularly national and international. Over the past 20 years, there has been a considerable increase in demand for more and better information owing to a growing public interest in the state of forests and their environmental and social benefits. Past surveys tended to concentrate on forest wood production. Inventory parameters should help us gain a better understanding of the status of biological diversity in a forest (for example, to define how much forests have evolved from their original form or to determine the areas occupied by different types of forestry in protected areas), or to understand forest health and vitality better. We also need to know more about forest potential to supply non-wood products, to absorb carbonic gases (through a more precise assessment of total biomass in the forest ecosystem) or to satisfy non-market demands such as recreation and ecotourism.
Where forest stands have developed rapidly, notably in tropical countries, it has become essential to assess how all these parameters change over time, necessitating a considerable increase in effort and expenditure. Obviously, to obtain reasonably accurate results, more samples must be taken to assess parameter variations between two dates than at only one date.
Surveys should also provide information on the effectiveness of forest management and, in particular, its sustainability. They should therefore help to assess the most important indicators of sustainability and the way in which these vary over time. This is not currently happening at the national and worldwide levels, as was shown at the Expert Consultation on Global Forest Resources Assessment 2000, held in Kotka, Finland, from 10 to 14 June 1996 and organized by FAO for the preparation of a worldwide survey of forests in the year 2000.
In addition, given the importance of non-forest trees for the environment and for local and sometimes national economies, it is not clear why so few efforts have been dedicated to them and why they are rarely taken into account in national surveys. Here again it will be necessary to expand the field of research and forest survey programmes, as in the Saharan Sudan region for example, where geographic information systems (GIS ) were applied to studying the operation and dynamics of forest parks.
Over the last 20 years, new technology has increasingly been used in assessing forest resources, including microcomputers, long-distance surveying via low-or high-resolution satellite, and GIS and geographic positioning systems (GPS). Useful new technological advances will follow and, as in the past, specialist forest surveyors in industrialized countries will be among the first to use them.
However, the main problems with forest survey methodology lie elsewhere than in the purely technological field. There are at least three other areas where problems can arise:
· the tools used must match the objectives and not vice versa; in particular, the concepts and classifications used must be useful to the end users, and are not necessarily the easiest to apply with available tools;
· considerable work still needs to be done on the international harmonization of concepts and classifications in order to facilitate better worldwide forest assessment and surveillance; the advances made in this respect by the Kotka III meeting mentioned above should be pursued energetically;
· finally, the survey capacity of poorer countries should be developed, not only for their own forest development needs, but also to improve worldwide forest evaluation through the active participation of their relevant authorities.
Threats to forest health: Prosopis trees in Mauritania defoliated by assort locust swarms
This last point leads to a general remark on the necessity of meeting these information requirements by making appropriate resources available to those responsible for forest surveys at the national and international levels and, most important, to FAO, which has the leading role in the worldwide forest survey, as confirmed by the United Nations Commission on Sustainable Development. National authorities and the intergovernmental bodies concerned, as well as the international scientific community, all agree on the importance of having both national and worldwide information on the state of forests that is as precise and diversified as possible. Unfortunately, these declarations are hardly ever followed up by action, and resources available in most countries and at international level are inadequate. Nevertheless, sustainable forest management will be impossible without knowing about all the forests where such management is practiced. A meeting of the international forestry community in Antalya (Turkey) strongly recommended that all governments allocate adequate resources to their forestry and international cooperation budgets.
Some aspects of the forest-agriculture interface
In general, the competition for land between forestry and agriculture is currently detrimental to the former in most developing countries and to the latter in industrialized countries. Within both of these groups of countries, the situations are clearly very different and depend on several factors, including the balance between urban and rural populations. the types of agriculture practiced, methods of landownership and use, and government land-use policies and incentives, which range from non-interventionism to fund planning directives and incentives.
In industrialized countries, natural or artificial forests have occupied marginal agricultural lands that were abandoned because they could no longer offer farmers a decent livelihood despite government subsidies. Very few countries provide enough aid to prevent rural depopulation. This reforestation is not necessarily viewed as a benefit, but rather as the abandonment and "desertification" of lands that were once shaped by rural people. Moreover, this abandonment leads to a higher fire risk in dry areas.
In developing countries, often obsolete regulations prohibiting forest clearing and cutting are being replaced by participatory and consultative approaches aimed at solving land use conflicts on a consensual basis. Experience has shown that "state" forestry alone is impossible, and in several countries programmes are under way to transfer ownership or usufruct rights in public forests to villages or individuals. As long as increasing population pressures (from both local people and, in some cases, immigration) do not force local people to deforest or overexploit forests for cultivation, animals or fuel, people can continue to harvest non-wood products, including food, enabling them-to maintain or improve their economic situation.
When forests have been completely destroyed, greatly reduced or become inaccessible, the use of trees within agroforestry systems allows rural people to diversify production and their incomes and to protect themselves from the risks of shortage or insolvency. An example of this can be seen on the high, densely populated plateaus of Kenya, where woody biomass on agricultural land is constantly increasing. Rural people decide to introduce trees and select species partially on the basis of the availability of plant material. but above all according to economic considerations. Moreover, economic considerations mean these people become involved in industrial wood production. After focusing on technical and biological aspects' agroforestry research and development work is now fortunately oriented towards the study of the socioeconomic factors that determine the choice of agroforestry system.
Trees and forests in and around towns
Urban and semi-urban forestry does not receive the attention it deserves from the forestry community, given that urban populations in countries all over the world are constantly increasing, very rapidly in developing countries, especially in Asia and Africa. There are many reasons for this neglect; the most important reason is that town councils and local and regional assemblies are responsible for managing towns and surrounding areas, and not ministries concerned with forestry. In effect, successes in urban forestry have often resulted from mayors who were convinced of the improvements in local standards of living that good tree and forest management could bring about. Urban forestry is also neglected because foresters tend to have less influence than they should, less than landscape designers and gardeners.
As in many other fields, the factors and problems encountered in urban forestry vary according to a country's level of economic development. Urban people in wealthy countries mainly demand recreation and pleasure (in all their forms) from trees and forests. In their special paper on urban forestry, Nilsson and Randrup (1997) underlined the priority that should be given to inventories and to the monitoring of trees and their health (which is even more important when the trees grow in difficult conditions and when numbers of them are old), and also emphasized the attention that should be given to soil characteristics and the use of environmentally friendly production techniques (for example less use of pesticides and heavy machinery). In view of the reduction of public finances and of the high cost of land in towns and their suburbs, in his voluntary paper, Konijnendijk (1997) poses the question as to whether the management of new green spaces should be entrusted to bodies other than town and local councils. The degree of consensus on the management of green spaces within urban communities varies; the values, perceptions, interests and importance attached to the trees and forests of a town can be very different from one community to another. At the same time, successful examples of tree planting and the establishment of green spaces to commemorate festivals or special days demonstrate that it is possible to involve urban communities in this issue.
In poorer countries, rural people who have moved to the city have immediate requirements for basic products: fuelwood, low-priced building materials, food and water for drinking and domestic use. Less essential, yet necessary to improve their quality of life, are the services that trees and forests can yield in and around towns: recreation and pleasure obviously, as in wealthier countries, but even more important, protection against water and wind erosion (and against dust-and sand-carrying winds), and protection of catchment areas around towns which supply water and enable urban wastes to be disposed of safely. To meet the requirements of these rapidly expanding city populations, foresters should cooperate with urban authorities and communities and all the nongovernmental organizations involved as far as their often limited resources allow, participating more than they did in the past in designing and implementing relevant projects in this area. Foresters could contribute to specific projects, i.e. systems for purifying and recycling waste-waters, which could be used to irrigate plantations, green spaces and forest belts, and the development of semi-urban agroforestry. Concerning this last point, it is important that foresters take part in the current research and development efforts by agronomists to increase agricultural production around towns, and that they promote the use of multiple-use forest trees in town environs to provide food products, forage and fuelwood.
Modifications to world forest cover and climatic change
In their own way, the numerous kinds of modification to forest cover affect atmospheric carbon dioxide (CO2) content and the carbon (C) cycle, and consequently the "greenhouse effect" and climatic change at world level. Opinions vary as to the exact figures, partly owing to inaccurate knowledge on the areas covered by different types of woody vegetation and on the links among these different vegetations and between them and other forms of land use (FAO's latest estimation of world forest resources has made an important contribution to this issue for the period from 1981 to 1990). According to Brown, Asan and Raev (1997) the situation can be summarized as follows: the world's total forest ecosystem contains 830 billion tonnes of C, 40 percent in the vegetation and 60 percent in the soil. This means that on average (and not taking into account the very high margins of error), each year in the period from 1981 to 1990 forests in temperate and boreal regions absorbed 700 million tonnes of atmospheric C, while changes in tropical forest cover resulted in a net emission of 1.6 billion tonnes of C. (These quantities of annual C storage or emission should be compared with the quantity of C produced by the burning of fossil fuels, which is in the order of 5.5 billion tonnes.) However, a more thorough analysis of the processes of the C cycle in the tropics would show that the net balance for that region was no more than 500 million tonnes. As a result, it is quite possible that world forests and their alteration make practically no contribution to atmospheric CO2 accumulations. This could change in the future, particularly with a global increase in the average age of forests in temperate and boreal zones (which is particularly likely to happen if a significant proportion of them are designated as protected areas).
Although the worldwide situation cannot be addressed with certainty, it is true that trees and forests can contribute to the absorption of atmospheric C if they are properly managed and used. Furthermore, it is now true that the impact of forest management on the C cycle can constitute an indicator of that management's sustainability. Nevertheless, with a few rare exceptions, the absorption of atmospheric C is not a principal objective of forestry management but only a secondary one. At the national and individual forest levels there are a great number of forest conservation and use measures and practices that reduce atmospheric C: change in systems of use and reduction in wastage; increases in standing volume through plantations and silvicultural interventions to enhance the productivity of existing stands; forest area conservation programmes; and greater demand for longer-lasting wood products. Industrialized and developing countries are now jointly carrying out forestry projects aimed at decreasing C emissions or at fixing atmospheric C. Among the 33 projects focusing on global warming initiated during the "joint activities" pilot phase of the convention framework on climatic change, nine concern the forestry sector.
Biotic and abiotic agents in forest deterioration
The higher incidence and gravity of insect attacks and diseases worldwide can be attributed to two factors: the decrease in natural forests and the increase in plantations and managed and planned forests, which have simpler ecosystems than natural forests; and air pollution in and near industrial and urban areas. Artificial and modified forests tend to have a limited genetic base, in spite of efforts (albeit still too modest) to increase the number and mix of species and their intraspecific variability. Today forest health in every country is also threatened by the greater movement of people and goods, including various plant materials, considerably increasing the risks of insect and disease diffusion.
In developed countries, the structures for researching, detecting and controlling diseases and insects are very old and generally well established, although they too suffer from current cuts in public spending. This does not prevent epidemics and insect attacks on stands of certain species or cultivars, sometimes over large areas, as in the Polish spruce forests which were attacked by the nun moth. Developed countries are also not safe from the mass reappearance of insect predators such as conifer bark beetles after prolonged drought. In addition, despite all the quarantine systems operating, these countries remain vulnerable to insect attack from neighbouring or even faraway countries, especially through imports. Finally, as they do not control the sources, forest managers in developed countries can do nothing about atmospheric pollution, which influences forest health in ways that are difficult to quantify.
The surveillance and maintenance of forest health in developing countries has not been a priority until now. There is very limited capacity for research, detection and control of diseases, and inadequate resources mean that quarantine legislation cannot be enforced properly. At the same time, more and more plantations are being established on very marginal former agricultural lands, often of exotic species that usually have an extremely narrow and little known (if not unknown) genetic base. In addition, the frequent absence of silviculture practices does not allow the necessary sanitary measures to be implemented. Against this background, the spread of insects and diseases from other countries can assume devastating proportions very quickly, with the response (sometimes with international aid) coming only after stands have been considerably damaged. Furthermore, favourable climatic conditions in the humid tropics can lead to the fairly rapid invasion of harmful exotic plants, against which existing resources are also inadequate.
One of the special papers on this subject (Mol, Kuçükosmanoglu and Bilgili, 1997) rightly emphasizes the changes necessary in foresters' perspective and attitude regarding fires. Obviously this does not involve lowering our guard against what in many cases remains a devastating scourge, destroying extensive wooded areas, either temporarily or even permanently across a generation, and causing the loss of property and sometimes human lives; nevertheless, it should be remembered that fire can equally be considered a useful tool in forest management and in land management in general. This is probably most commonly seen in controlled fires, which reduce the amount of combustible material in the vegetation and undergrowth before the dry months and thus diminish the risk of more destructive fires at the height of the dry season.
The most common examples of controlled fires in the dry tropics are bush fires, particularly in Africa. These are part of a very old tradition aimed at promoting the regrowth of grasses for feeding livestock and to facilitate the capture of wild animals. The reduction of available land for agriculture owing to an expanding rural population and continuous environmental destruction from repeated fire outbreaks are factors that require public awareness campaigns for local people on the benefits of controlled fires. This was done successfully in Guinea through local radio stations, as Kane (1997) points out in his voluntary paper. In African countries bordering the Mediterranean, the presence of people in rural zones and their use of forest tracks mean that fire does not represent a serious problem in that subregion for the time being.
Every year, most of the areas destroyed by fire in the Northern Hemisphere are in the vast forest areas of Canada, the United States and the Russian Federation; countries which have good forest fire detecting and fighting resources, although the Russian Federation is experiencing difficulty in maintaining existing capacity. Other black spots for forest fires are European countries bordering the Mediterranean. Unlike the situation on the other side of that sea, forest areas are underutilized or unused by a rural population that is rapidly dwindling; the consequent biomass accumulation, together with the invasion of hordes of town-dwellers and careless tourists every dry season, generates favourable conditions to the rapid spread of fire in spite of the undeniable progress made in the detection and organization of fire control. This progress has been possible because of the relative priority that national and local authorities give to forest fires, owing in part to the high media coverage of large fires, which is far greater than that given to diseases and insect attacks on forests.
Resources for controlling forest fires are expensive and should therefore be designed, developed and maintained at the highest planning levels, i.e. at the national, federal or even international level; international cooperation among neighbouring countries should be actively sought. Unfortunately, examples from the recent past have shown that blind self-interest and the refusal of local, provincial and even national governments to share their firefighting resources can only worsen the damage to their forests.
Forest surveys that are more appropriate to needs
Taking into account the growing social interest in the state of forests and the pace at which they are being modified, it is now more important than ever that the choice of survey parameters and the precision of assessments should be the subject of widespread consultation with potential users, first and foremost the relevant decision-makers and planners.
Considering their essential role in good forest management, forest assessment and surveillance only rarely receive the priority they deserve. Forestry bodies should allocate adequate resources to assessment and surveillance and, if necessary, obtain extra funding. As decision-makers tend to show little interest in this subject, awareness-raising activities will be clearly necessary in many cases.
The lack of forest inventory resources is worse in developing countries. and thus it is vital to build the necessary capacity.
Although the establishment of networks and centres at the subregional and regional levels is a partial solution, it does not rule out the need for support from the donor community.
It is not enough to define the indicators of sustainable forest management; these indicators should also be evaluated on an ongoing basis at the various planning levels, including the national level. Forest surveys should make it possible to evaluate as many of these indicators as possible, in order that they can be linked to survey parameters and that surveys can incorporate new parameters if necessary. Better knowledge and monitoring of world forest resources requires international harmonization of the concepts and classifications used in the surveys. This must be pursued without delay. In turn, this harmonization will facilitate the equally important harmonization of sustainable forest management indicators.
As was shown in the section, The evolution of forestry information requirements, p. 12, the demand for forestry information has continued to grow over recent years, requiring greater research efforts on subjects such as in-depth definitions of the various degradation processes and of the status and evolution of biodiversity.
Better management of the forestry-agriculture interface
To improve knowledge of the interface between forests and agriculture, forestry surveys at all levels should aim for a better coverage of the trees that are growing in clumps or rows on agricultural and pastoral areas. Another technical priority area is the study of biodiversity status and evolution for forestry species in agroforestry systems and the promotion of practices to maintain or increase this biodiversity.
However, future priorities for agroforestry research seem to lie more in the socio-economic area and must take particular account of farmer research into risk reduction and the need to diversify production. In particular, forestry researchers and practitioners should support agriculturists in their efforts to produce wood for fuel, services and industry, thereby helping to reduce pressure on existing forests.
Greater forest community participation in the improvement of urban standards of living
The section, Trees and forests in and around towns, p. 14, mentioned the apparently inadequate involvement of the forestry community in urban and semi-urban forestry initiatives and foresters' difficulty in extending beyond the natural context for their activity, i.e. the rural world. Some of the problems requiring corrective measures have already been mentioned. One of the most important fields in all countries is the use of wastewaters: the irrigation of urban and semi-urban trees and plantations, which act as a sort of "green filter", should be the object of trials and development in many places.
In addition, as town authorities are primarily responsible for managing towns and surrounding areas, the twinning of towns represents an international framework for forestry action, notably twinning between the Southern and Northern Hemispheres.
A greater forest and forest management contribution to mitigating the "greenhouse effect"
The adaptation of forest management to increase carbon fixing and reduce atmospheric carbon emissions assumes better knowledge of the state and temporal evolution of forest ecosystem biomass. This is an area where tree studies and forest surveying have much progress to make. The recent FAO publication on this subject (FAO, 1997b) is a useful contribution and it is to be hoped that it will be followed by many others.
Although carbon fixing is not the main objective of forest management in most cases, management plans and practices can be adapted to increase the role of forests in reducing global warming. The section, Modifications to world forest cover and climatic change, p. 15, outlines examples of what can be done to this end at different stages of management, all the way to and including the use of processed products.
Moreover, it is important that the forestry community is aware of the changes that could affect forests in the medium and long terms within the various scenarios of global warming and that the necessary adaptations in forest management are identified.
Strengthening phytosanitary initiatives
Besides the much publicized episode of the shrinkage of European forests, forest health does not attract as much media and public attention as forest fires, which are far more spectacular and dangerous to humans. As was seen in the section, Biotic and abiotic agents in forest deterioration. p. 16, developed countries have thus far managed to preserve the basic resources for surveillance, prevention and control of the diseases and insects that attack forests.
This is not the case in most developing countries. One way to remedy this state of affairs, albeit only partially, is to set up and operate subregional and regional networks to permit the exchange of knowledge and experiences concerning insect biology and disease cycles, and methods for prevention and chemical and biological control. An example of such a network is that established in East Africa after various insects recently attacked forestry plantations in this subregion. Networks also allow countries to identify common strategies for prevention and control - in particular, harmonization and reinforcement in the application of quarantine measures - and, more generally, to interact in all aspects of integrated phytosanitary management.
Among the initiatives to be taken worldwide, we could consider the one already under way to develop directives on the risk-free transfer of plant material, and the preparation of a worldwide information and early warning system for diseases and insects. This system is particularly important as insects and diseases constitute a transboundary problem.
Better fire control and management
The efficacy of controlled fires in various situations and ecological zones is well acknowledged, but controlled fires remain underused. Much can be done towards encouraging and raising the awareness of rural people in poorer countries where they still make up a considerable part of the population and where public funds are insufficient for the task.
Public awareness programmes are also an essential element in forest fire prevention in richer countries. Databases on forest fires are an essential tool, priority should be given to setting up databases and making them operational, as they target prevention campaigns better through a precise identification of fire causes, agents and their behaviour.
Finally, the importance of strengthening international cooperation in this area cannot be overemphasized, particularly, though not exclusively, through the sharing of fire-fighting resources among neighbouring countries.
Brown, S., Asan, U. & Raev, I. 1997. Forests and climate change and the role of forests as carbon sinks. Special paper presented at the Eleventh World Forestry Congress, 13-22 October 1997, Antalya, Turkey.
FAO. 1996. Forest resources assessment 1990. Survey of tropical forest cover and study of change processes. FAO Forestry Paper No. 130. Rome.
FAO. 1997a. State of the world 's forests. Rome.
FAO. 1997b. Estimating biomass and biomass change of tropical forests. A primer. By S. Brown. FAO Forestry Paper No. 134. Rome.
Kane, R. 1997. Suivi satellitaire des feux de Guinée et de l'impact des campagnes de sensibilisation de la radio rurale. Voluntary paper presented at the Eleventh World Forestry Congress, 13-22 October 1997, Antalya, Turkey.
Konijnendijk, C. 1997. Urban forestry in the Netherlands: lessons from the past. Voluntary paper presented at the Eleventh World Forestry Congress, 13-22 October 1997, Antalya, Turkey.
Mol, T., Kuçükosmanoglu, A. & Bilgili, E. 1997. Forest fires in a global environment and changing attitudes toward fire. Special paper presented at the Eleventh World Forestry Congress, 13-22 October 1997, Antalya, Turkey.
Nilsson, K. & Randrup, T. 1997. Urban and peri-urban forestry. Special paper presented at the Eleventh World Forestry Congress, 13-22 October 1997, Antalya, Turkey.