| Reforestation in the Pacific Islands |
This manual has been designed as a reference and technical information tool for use by community development workers and others interested in forestry and reforestation projects in the islands of the South Pacific. It is an attempt to present--in clear, non-technical language--background and "" how to" information necessary for Peace Corps Volunteers and other forestry workers to understand the basic issues surrounding problems of deforestation and to initiate and plan local-level reforestation projects.
Traditionally, transfer of information on forestry management techniques has relied heavily on application of temperate zone techniques to tropical areas. But such techniques do not always work well when applied under widely different environmental and social systems. This manual represents an attempt to provide an easy-to-use information resource especially geared toward forestry-related activities in the tropical Pacific islands.
No single manual can include all the information the forester may need or want to know. The community forester must be prepared to face a range of different situations and problems and to adapt to changing circumstances. Even within the South Pacific island area, conditions differ greatly. There are a variety of environmental issues, languages, and cultural differences between and within island groups. Time spent consulting host country experts may prove extremely useful to the novice forester.
Successful community forestry projects, like other development efforts, must take into account the needs and desires of community members, the physical and environmental factors affecting the locality, and the availability of materials, resources, and skills necessary to carry out each step of the project.
This manual provides basic information about things the forester should know. It should assist the forester in understanding:
• The causes and effects of deforestation.
• The potential of forestry projects for improving quality of life and the environment.
• Environmental, sociopolitical, and economic factors to consider in implementing forestry projects.
• Forestry systems applicable to the Pacific, especially agroforestry systems.
• Techniques and field methods for establishing and maintaining successful projects.
Forestry may be defined as the practice of managing forests and forest related resources for the purpose of achieving desired goals, such as conservation or production. Forests provide numerous benefits, particularly in conservation of natural resources and production of important commodities--food and fodder, fuel and timber. Forestry programs may have many different goals, including afforestation, fire protection, watershed management, erosion control, agroforestry, fuelwood production, and regeneration of species diversity or natural habitats for wildlife.
Forestry practices differ from place to place. They depend upon the natural resources, land use patterns, and policies and regulations that are in effect. One Pacific island country may have young, or maturing, forests that are the symbol of a recovery from past mismanagement or natural disasters. In another country, mature forests may be under severe pressure and never fully recover. On other islands, forestry projects may have reclaimed denuded slopes, turning them into viable food and wood-producing projects.
Humans have always impacted the world's forests. Humans probably changed vegetation patterns first with the discovery of fire, which they used to drive animals toward waiting hunters. With the advent of farming, fires were used to clear fields for livestock grazing or cultivation. American Indians cleared forests with fire to extend the range of the buffalo For over 5,500 years a burgeoning Chinese population, requiring enormous amounts of food and fuel, expanded into forested lands, cut the trees, and planted crops As early as 3000 B C the Phoenicians used wood to produce pottery, metals, and glass products for a world market The famous cedars of Lebanon were used to build ships, palatial temples, and palaces. Plagues, wars, and agricultural and industrial needs decimated vast stands of European forests. It was not until coal and steel replaced wood for heating and shipbuilding, and the concept of sustained yield became popular, that the pressure on European forests was reduced. Today, forest clearing in Africa and Southeast Asia remains a serious problem. Large stands of previously unreachable tropical forests are being cleared for agriculture, cut for firewood, and harvested to supply timber to a voracious foreign market
(For additional information see Carter and Dale, 1981.)
Man's historic use of forest byproducts has reduced the world's original forest area to at least one-third to one-half its original size. According to the World Resources Institute, at the current rate of destruction, at least 225 million hectares of the world's remaining tropical forests will be deforested and 10 to 20 percent of all animal and plant life will be lost by the year 2000.
This wholesale loss of forested lands has had a number of adverse effects. Tropical forests provide humanity with a cornucopia of benefits. Tropical forests are living museums and laboratories that have yielded only a tiny fraction of their treasures to scientific study. Many useful chemical products essential for making medicines and pharmaceuticals originate in tropical plants. More than 50 percent of modern medicines come from the natural world, many from tropical forests.
Industrial products derived from moist tropical forests include volatile essential oils, gums, resins, latexes, and other exudates, steroids, waxes, rubber, fibers, dyes, tanning agents, turpentines, edible oils, rattans, bamboo, flavorings, spices, and pesticides.
The cutting of forests and pressures on forest lands have led to soil erosion, water shortages, landslides, flood damage and destruction of productive lands, and siltation of rivers and streams. This is of particular concern in the Pacific islands, where forested watershed areas located upstream from agricultural lands are vital to agricultural productivity. These upland water catchments are the principal sources of water for all downstream uses, and their destruction can cause serious harm to the environment and to people who make their living from the land. Furthermore, rain forests are home to 200 million people, who rely on the forests for the necessities of life. Tropical forests provide them with fruit, nuts, and honey, along with fibers and wood for building, fuelwood for cooking, lighting and heating, and fodder for livestock raising.
Coastal dwellers relying on fresh and salt water fish products are affected as well. Soils eroding off bare slopes into streams may eventually be discharged into estuaries and mangrove swamps that serve as breeding grounds for fish. Increased sedimentation can eliminate breeding grounds, as well as destroy aquatic plant material that is an integral part of the food chain This destruction will ultimately ruin the local fishing industry.
Perhaps the most important aspect of deforestation is the effect on the environment. Tropical forests exhibit an incredible array of life. During the ice ages, they served as refuges where less hardy species survived and later repopulated the temperate zones. Whereas temperate, northern forests are unlikely to contain more than 10-15 tree species per hectare, a single hectare of Amazon rainforest has been known to contain up to 230 species. A natural forest ecosystem is an integrated web of organisms that has developed over millions of years into a state of dynamic equilibrium, wherein it is able to adjust to changes in the environment and reestablish a balance. When a great deal of stress is placed upon the system for a long period of time, the system is less able to adjust to the changing conditions. This often results in the destruction of a portion of the wide array of plant and animal species indigenous to the system (see Illus. 1-1). The resulting degradation could even generate local or regional climatic changes, with as yet unknown consequences.
Island species of flora and fauna (plants and animals) are particularly vulnerable to prolonged periods of stress. In general, islands have less species diversity than do most continental land areas. With fewer species, the competition is lessened, as is the resistance of any individual species to introduced (non-native) pests, diseases, and other stresses.
Forestry projects can help resolve these problems by restoring the productive capability of the land and by preventing further destruction. (For more information, see Jordan and Farnworth, 1982; Spears, 1982; and Poore, 1983.)
There are many factors influencing the cutting of trees and the depletion of forest resources in the Pacific islands. In recent years, increasing pressure has been placed on forest lands for economic and social as well as political reasons (Plumwood and Routely, 1982). The social, economic, and environmental causes and effects of deforestation are closely interlinked, and any proposed strategy for reversing the trend must consider these linkages.
The major causes of deforestation in the South Pacific islands are summarized below.
The main effect of human intervention in forest areas has been to decrease the extent of the forest and to change the types and quantities of vegetation. When land is intensively cropped and then abandoned, the natural tree cover and soil fertility may never return. Instead, shrub and grass species may become the dominant type of vegetation. Once established, these species are difficult to eradicate. This has already occurred in many islands with the establishment of Imperata grasses.
The high population growth rate in the Pacific islands (3-5%) has contributed to increasing pressure on land and other natural resources. As population increases, the amount of forest land usually declines, because demand for land for food production and other uses intensifies.
Increases in population, as well as migration among and within island regions, have created an ever-increasing demand for land that can be used for- settlement and/or cultivation. As population increases, the size of individual farms or plots usually decreases. Particularly for subsistence farmers, cultivation intensifies as plot size is reduced. This usually results in soil depletion and related problems such as declining crop yields. In many of the south Pacific islands, land ownership is tribal or clan-related. This system can be a major concern in forest management. Additionally, population pressure forces many farmers onto land unsuitable for cultivation.
In some areas, disputes over land ownership may result in misuse of the land or poor land management practices. Without clear title to the land, people tend to be less concerned with proper management.
The construction of roads and expansion of transportation networks into forested areas also lead to the destruction or damage of forest lands. The new roads open marginal lands to migrants, who often lack the skills or incentives to properly manage the land.
Shifting cultivation (swidden agriculture) is a common practice in many regions of the world. In the Pacific islands, shifting cultivation usually occurs on steep, sloping lands; tilling with draft animals, machinery, or by hand takes place on the flat lowlands. In shifting cultivation, farmers intensively crop a given area of land for a few seasons until the productivity of the land and crop yields decline. They then leave the exhausted land fallow (uncultivated) and move on to farm elsewhere. The natural cycle of regeneration of land takes about 25 years; in order for soil fertility to be restored, the land should lie fallow for at least five to ten years. But because of increasing pressures for land, in many areas of the Pacific this "resting" time has been reduced to 4 years or even eliminated entirely.
Slash and burn techniques for clearing forests are associated with shifting cultivation practices. They enable the farmers to quickly and easily prepare new land for cultivation. The combination of shifting cultivation and related practices often leads to deterioration of soil conditions and loss of protective ground cover. These practices can be particularly damaging to the land, causing rapid depletion of soil nutrients and loss in productivity, erosion, landslides, uncontrolled fires, and flooding.
Increased population pressures often lead to the use of margin lands, or fragile areas that are ill-suited for cultivation under normal circumstances. Overgrazing of livestock can also lead to losses in productive
capacity. Animals tend to eat favorable vegetative species, leaving behind hardy weeds. Unmanaged herds tend to compact soil, thus reducing water infiltration, exacerbating runoff, and precluding the establishment of favorable plants.
Monoculture, or single crop systems, may reduce species diversity and resistance to disease and pest infestations. Continuous corn or upland rice cultivation on steep slopes promotes erosion. Unless proper long-term management techniques are applied, intensive cropping of single species can also deplete soil fertility.
Inadequate Forest Management Practices
In many regions, there has been insufficient education, promotion, coordination, and enforcement of proper forest and watershed management practices. Natural mangrove forests on many islands have been destroyed by overcutting and clearing by loggers and farmers. The revegetation of these lands is often not enforced, or is difficult to enforce due to the demand for tillable land. Farmers with poor land management skills receive limited training due to underfunded government programs. In many cases, government bureaus in charge of forestry and agriculture fail to coordinate related programs, thus undermining long-term government objectives. Even where properly conceived programs do exist, enforcement and public support for them may be limited. Environmental education and extension efforts are required to teach officials and farmers the importance of sound management techniques.
Economic Pressures--Demand for Timber, Fuelwood
The demand for timber has increased, in part due to the growth in world market demand and in part to pressure on small- island economies to develop cash-generating activities to pay foreign debts. Between 1963 and 1983 the amount of wood produced for markets increased from 1.8 to 3.0 billion cubic meters. Ten developed countries account for 65 percent of the total value of timber imports.
Over the past 35 years the production of fuelwood has more than tripled. Nearly 1.5 billion people in 63 countries, or about 60 percent of the people who depend on fuelwood as their principle source of energy for cooking and heating, are cutting wood faster than it can grow back. At present consumption rates, the estimated fuelwood deficit will double by the year 2000. (For more information, see Arnold, 1983.)
Although typhoons, floods, landslides, fires, and other natural disasters occur naturally, their frequency and impact can be significantly increased when the delicate balance of the ecosystem is disturbed, or when natural protection is lessened.
Food and Fodder--Agroforestry
The natural forest provides an abundance of food resources to both people and animals. Since settlement and cultivation of forest land areas began, people have learned to use the forest in various ways, including the application of agroforestry, in which both food crops and trees are grown on the same land for a variety of end uses. More recently, the concept of agroforestry has gained greater attention as a means of alleviating some of the pressure for tillable land and protecting forest and land resources. (See Domingo, 1981; 1980; Spurgeon, 1979; King, 1979a; Douglas and Hart, 1976; Stewart, 1981; and Adeyoju, 1980.) Agroforestry is an integrated cropping system in which a mix of outputs may be produced on a continuing, sustainable basis. These products may be roughly divided into food and fodder outputs from both tree and agricultural crop cultivation, and wood products from the trees.
Fuel for cooking, lighting, and heating is extremely important to the upland farmer. In most areas wood is the cheapest, most familiar, and most easily available form of fuel. Fuelwood for use on upland farms--fallen limbs and branches and dead trees-- is usually collected from forested areas. In some regions, the forest areas have been destroyed or have receded so that the time and effort required for collection and preparation of wood for domestic use has become excessive. The shortage is so extreme in some areas that people are forced to cut down productive trees for use as fuel.
In agroforestry projects where the major products are food and fuel, the species may differ, but the basic techniques for cultivation and planting are similar to those in cropproducing agroforestry systems. The specific techniques for each type of agroforestry project are covered in Chapter 7.
In addition to its use as a domestic fuel, wood may also be in demand for commercial uses: wood chips used as a boiler fuel in place of gas or oil for steam production or electric power generation; production of chemicals or liquid fuels through fermentation or gasification; or small-scale commercial fuelwood or charcoal production for outside (usually urban) markets. Commercial fuelwood production may take place in a large corporate operation or may be practiced by small farmers, and may be part of monoculture or intercropped agroforestry systems. This manual is primarily concerned with the considerations for small-scale agroforestry systems.
In upland areas, timber is used for construction of poles and fencing and for other farm purposes. Timber may also be in demand where markets for pulpwood and electrical transmission posts exist. High-quality timber is also a major export item for many Pacific countries.
Environmental Benefits of Forests
As mentioned earlier, intensive cutting of forests and cultivation of marginal lands has resulted in rapid soil erosion and decline in productivity in many areas. Under certain conditions, erosion and declines in productivity can be effectively controlled through proven methods of forest farming. Besides requiring low inputs, forest farming techniques that utilize specific plant species can stabilize soils on sloping lands, help maintain and improve soil fertility, and positively impact the microclimate of an impacted area.
Particular tree and plant species, having deeper, more extensive root systems than other species, function to hold down soil on lands and reduce its tendency to erode when impacted by water and wind. This protective characteristic is enhanced when planted on sloping lands.
Tree and plant litter, consisting of leaves, branches, etc., also serve as ground cover, protecting the soil surface from the pounding of heavy rains and consequent splasherosion. The organic matter, together with the root system which penetrates into deeper subsoil, increases water filtration and absorption of water through the soil. This is particularly important during times of heavy rainfall (see Illus. 1-2).
By increasing soil stability, trees and plant cover may also prevent the damaging effects of siltation on streams and other water supplies, including irrigation channels, that may be caused by movements of large masses of soil.
Extremes in water levels--very low levels or flooding--may also be regulated with proper forest management. Well planned placement of vegetation may also serve as an effective windbreak, reducing wind erosion and damage to crops.
Both the tree and plant foliage, which serve as a windbreak and canopy, and "mulch" created by tree litter, provide shading and thermoregulation (temperature regulation) by reducing direct solar radiation upon the soil surface and moderating the water flow, thus regulating moisture content of soil. By reducing sunlight, the effects of high temperatures--such as hardening or "baking" of the soil surface, which causes impenetrability, and increases in evaporation of surface water--are reduced. By maintaining the temperature balance at the soil surface, the microclimatic conditions for decomposition of organic matter and release of soil nutrients are improved. The forestry canopy also protects the microclimate from drastic fluctuations between day and night temperatures. A full or partial canopy will also ensure the viability and productivity of light intolerant plant species. Because coffee trees are an understory plant, under certain conditions productivity is increased when grown under other tree species. Leafy vegetables are also sensitive to strong sunlight. Proper shading can extend their growing season.
The natural forests provide many other non-economic benefits that are sometimes difficult to measure and not always recognized by individual farmers or policy-makers.
• Forests, through their photosynthetic and filtering actions, provide a natural source of oxygen and pollution control.
• Wildlife habitat is another important forest product.
• The diversity of plant species in the forest and their spatial arrangements can deter insect proliferation. Careful study of these species and their interrelationships may provide important lessons for farmers and agronomists.
• As stated, 50 percent of the world's medicines come from natural plants.
• Plant species are also a source of aesthetic and recreational pleasure, and can serve as a "classroom" for important environmental education work.
The primary reasons for implementing forestry programs and projects are as follows:
• Conservation and protection of land quality, species diversity, and natural habitats for economic and non-economic benefit.
• Increase of productivity to develop economic and food production potential.
The type of project chosen and the species selected for forestry projects depend upon the specific conditions and needs of the project area. In the following chapters, we will discuss how the community forester can help to determine these needs.