Global demand for all wood products is increasing and, as a result, deforestation of natural forests is continuing at an alarming rate. FAO's recently-completed Forest Resources Assessment of the tropical countries estimates that, worldwide, 15.4 million ha of natural forests are being lost annually. Within this Region the rate of deforestation between 1981 and 1990 equalled 3.9 million ha annually or 1.2% of the total forest cover - almost double the annual rate of 2.0 million ha during 1976-1980.
The difference between supply from the natural forests and demand must be met from planted trees, and the rate of forest plantation establishment has increased sharply in the last decade, particularly within this Region. According to FAO estimates, the annual rate of plantation establishment in tropical Asia and the Pacific during 1981-1990 averaged 2.11 million ha/yr, or 81% of the global increase in forest plantation during this period. Species of Eucalyptus have been dominant components of such plantation programmes. Over 5 million ha of Eucalyptus plantations now exist in the Asia-Pacific region, comprising 8% of the total area of plantations.
However, the planting of Eucalyptus has not occurred without controversy. During the 1980s serious criticism arose, first in India and later elsewhere in the Region, concerning alleged adverse effects of species of Eucalyptus on soil nutrient status and soil water relations, on soil erosion and on wildlife. In 1985, FAO reacted to this debate by commissioning a study, funded by the Swedish International Development Agency SIDA, entitled "The Ecological Effects of Eucalyptus", published as FAO Forestry Paper 59. This publication and others which followed stimulated further discussion and a number of new studies on the various effects of Eucalyptus plantings.
The Regional Expert Consultation on Eucalyptus, held in Bangkok 4-8 October 1993, reviewed recent findings on the social, economic and environmental effects of Eucalyptus plantings. The conclusions reached and the strategies recommended are summarized below:
· There is now recognition by all who attended the Consultation that the problems and conflicts formerly blamed on species of the genus Eucalyptus arise more from the insensitive application of government policies on afforestation and from social injustice.
· Eucalyptus species can provide many benefits very quickly, ranging from industrial wood and fibre, to poles, posts, timber and fuelwood for household use, nectar, essential oils and tannin, and thus can relieve pressures on natural forests for these products. Services such as windbreaks and shelter belts may also be provided by Eucalyptus spp.
· Decreased forest resources and increased demand for forest products mean that all 14 countries reporting to this Consultation expect to expand their plantation programmes; only two of the countries reporting do not expect to expand the area of Eucalyptus species within the plantation programme.
· Land within forest reserves is generally neither sufficient nor is it always suitable for conversion to plantations. Planting of trees, including Eucalyptus spp., on private and communal land should thus be encouraged and obstacles such as land tenure issues, disincentives in the form of regulations, weak market structure and misinformation be removed and financial support provided, where possible.
- Government agencies should give more freedom and responsibilities to local communities, user groups and private enterprises of various kinds in the establishment and management of manmade forests.
- Where the constraints exist, the governments and local authorities should take action to review existing arrangements for land tenure and other matters affecting the flow of goods and services from plantations, and rectify the situation as appropriate.
- Government agencies should encourage the producers of forest products to establish and strengthen cooperatives and other associations. The government agencies should adopt policies, strategies and programmes to extend planning and advisory services for the sound development of the marketing mechanisms for forest products.
- All concerned in the private and public sectors should increase the flow of information on every aspect of eucalypt plantations, including environmental, social and economic impacts. Extension services should be strengthened.
- Farmers' cooperatives and private companies which grow trees should be provided with a package of incentives, which may include credit, grants, subsidies, or tax exemptions and insurance.
· In some places, planting of Eucalyptus on public or communal land has proved to be socially acceptable and economically viable. In other places, problems have occurred due to insufficient involvement of local communities in the planning, establishment and management of such plantations due to disregard for their needs.
- Plantation development should take note of the requirements of existing populations for forest products and other goods and services. Furthermore, local communities should be encouraged to participate in plantation establishment, management and utilization.
- Those responsible for plantation developments on common land should incorporate mixtures with other species in demand, including indigenous species, as well as the inclusion of species yielding non-wood forest products.
· Legislation and policies on manmade forest development cannot be formulated in isolation but must be considered within the framework of national forest laws and national economic and social development policies.
- Policies on manmade forest development should have four major aims: 1) to meet the increasing demands for timber, fuelwood, fodder, fibre, paper etc. (production issues); 2) to reduce heavy pressure on natural forests (protection/conservation); 3) to contribute to community development (social and economic issues); 4) to rehabilitate and restore damaged forest ecosystems in places where natural recovery cannot be foreseen in a short period (environmental aspects).
- Provision should be made for participatory approaches to forest plantation establishment and management.
- A review and updating of national land use and forest policies should be undertaken to ensure that these policies are socially fair, economically viable and environmentally sound.
· Environmental effects of Eucalyptus include impacts on soil water, soil nutrients and soil erosion; allelopathic effects; attacks by pests and diseases; and impacts on wildlife and plant diversity. Most adverse effects can be minimized through proper plantation design and management.
- Where water is scarce or demanded by other sectors, special care should be given to adjust the eucalypt biomass production to match the amount of water available. The water consumption needed for eucalypt plantations can be reduced by planting fewer trees per unit area or by thinning existing plantations.
- In general, under rain fed conditions, where annual rainfall is less than 400 mm, other crops may not be able to grow with eucalypts. Where the annual rainfall ranges from 400 to 1,200 mm, a careful planning of the water balance is recommended where other crops are established with eucalypts. Careful monitoring and management is necessary for such mixed plantations.
- The foliage and bark of eucalypts should be left on the plantation floor after harvesting the wood, since these components have relatively high contents of nutrients. Soil nutrient balance and recycling efficiency should be continuously monitored from one harvest to the next.
- If risks of soil erosion are present, disturbance should be minimized, and ground cover vegetation should replace mechanical weed control. Tree spacing may have to be widened to allow permanent, living ground cover to develop. Contour ploughing must be adopted on sloping land, physical barriers such as bunds or rock walls should supplement tree barriers on steep slopes.
- Where annual rainfall is less than 400 mm, field trials should be conducted, to demonstrate whether allelopathy is a factor to be taken into account with regard to the specific eucalypt/crop mixtures planned. If it is proven, allelopathy can be minimized, even in dry climates, by cultivation methods, fertilization and irrigation, and also by the selection of compatible crops.
- Pests and diseases should be closely monitored. Accurate site matching and selection of resistant eucalypt species, provenances and varieties can help to reduce the incidence of pests and diseases. Further development of biological control measures should specifically be encouraged.
- The biodiversity of eucalypt plantations cannot be compared with that of intact natural forests of most types and, although eucalypt plantations have more diverse populations of fauna and flora than many types of degraded lands, eucalypt plantations should not replace healthy and undisturbed natural forests, if the conservation of biodiversity is a priority. The plantations may, however, have a value as buffer zones around nature conservation zones. It is further recommended to plant eucalypts in a mosaic fashion with native vegetation, where feasible.
· Several gaps and weaknesses in the knowledge regarding the sound management and utilization of eucalypt plantations exist. The Consultation thus recommends that the following research and development activities be undertaken:
- Site matching studies of species, provenances and varieties.
- Studies on mixtures of eucalypts species with other tree species and agricultural crops in various forms of land use, instead of, or as alternatives to, monoculture of eucalypts.
- Studies on nutrient cycling within poor soils vis-a-vis good soils.
- Tree breeding programmes, leading to the production and supply of genetically improved seeds and vegetatively prepared planting materials.
- Collection of growth and yield data on eucalypt plantations and determination of the optimum stocking in order to minimize the adverse environmental impacts caused by the high biomass production of eucalypts.
- Studies on social and institutional issues concerning eucalypt plantations, including forest policies, legislation, land tenure, and the roles of producers (farmers, government agencies and private companies) and local organizations in the establishment and management of manmade forests, especially those composed of fast growing species.
- Studies on the economic impacts of eucalypt plantations, including costs and benefits, product diversification (e.g. honey, essential oils, etc.), processing and marketing mechanisms.
- Development of monitoring and evaluation systems to measure the social, economic and environmental impacts of eucalypt plantations.
- Development of mechanisms to collect, evaluate, analyze and disseminate research results and other relevant information on Eucalyptus spp.