This section briefly summarizes the bio-physical characteristics of five important forest bio-regions in Southeast Asia: lowland evergreen rain forests, swamp forests, mangrove forests, monsoon forests, and montane forests (see Figure 3). Due to their natural features, each major forest type plays a unique role in the region as a distinctive habitat for biodiversity, in the way it interacts with climatic and hydrological patterns, and in providing resources for human societies. In each forest environment described below community forestry exists and is evolving in distinctive ways, with these different physical contexts presenting specialized needs and opportunities for local stewards.
The forests of Southeast Asia are largely located in tropical biomes. The dominant environ- mental characteristic of the tropics is the consistently high temperature throughout the year that shapes the tropical climate and ultimately the structure of biotic communities. Next to heat, precipitation is a critical element, often heavy and variable. As one moves away from the equator, annual precipitation declines and there is greater variation depending on the season. According to Hutterer: "As dry seasons become longer in the outer tropics, one eventually encounters climates with year-long droughts. This situation is reflected in a coarse subdivision of tropical nature into 'humid,' 'seasonal,' and 'arid' tropical environments" (
Note 1) These climatic variations are reflected in tropical forest environments and the ways in which human communities interact with these different ecosystems. The types of knowledge and technologies that have been developed over the centuries to manipulate forests are in response to the specific features of each natural environment. It is therefore important to examine the particular physical context to which communities relate.Positioned between the Pacific and the Indian Ocean, approximately one-half of the land area of Southeast Asia is composed of island arcs. As a consequence, the region's climate and flora are shaped not only by its position near the equator, but by the movement of monsoonal air exchanges between the Pacific and the Asian mainland. As a result of this climatic pattern, the Malay Peninsula, much of Sumatra, Borneo, western Java, the Celebes and eastern Philippines possess a humid climate, with extended dry seasons found in eastern Indonesia, the western Philippines, and northern parts of mainland Southeast Asia.
The equatorial flora of Southeast Asia is one of the richest in the world. A single 50-hectare plot of lowland rain forest in Pasob Malaysia possesses 830 species of plants over 10 mm in diameter; over 1200 species were identified in a similar sample area in Sarawak (
Note 2). Of the 250,000 flowering plants identified worldwide, 15 percent occur on the Malay Peninsula and the Southeast Asian archipelago, a region referred to by botanists as "Malesia." (Note 3) Plant families that characterize forests of the region include Myristicaceae (the nutmegs), Annonaceae (the soursops), Musacaeae (the bananas), Ebenaceae (the ebonies), and, most importantly, Dipterocarpaceae. The island of Borneo alone includes 287 species from the Dipterocarpaceae family and it is the big trees from this group that comprise much of the canopy and emergent trees in many Southeast Asian lowland evergreen forests.The species-diverse, closed-canopy rain forests of Southeast Asia extend across the archipelago, gradually shifting to monsoon forests in the southeastern islands of Indonesia but reappearing in the Moluccas and New Guinea. Rain forests are also found in mainland Southeast Asia, measuring more than two meters of annual rainfall and with a dry season of less than five months. This includes parts of Burma, Thailand, Cambodia, Laos, and Vietnam, extending into southern China, Bangladesh and Assam. As seasons become more distinct farther from the equator, the floristic character of tropical forests is altered and they become simpler in structure (
Note 4). Greater seasonal variation in temperature and moisture may result in a lower forest canopy, reduced species diversity, and diminished stand density. As forest density and height decline, so does the biomass. In areas with extended dry seasons, monsoon forests are more common, with open woodlands and scrub forests common in the more and regions.Botanists have broadly divided Asia and the Pacific into five floristic regions: India, Indo-China, Malesia, Australasia, and Pacific. This report will consider two of these regions: the Malesia, which comprises Malaysia, Indonesia, the Philippines, Brunei, and Papua-New Guinea; and, Indo-China, whose floristic region stretches from Burma to southern China, and south to Thailand. Malesian flora encompasses at least 35,000 species of flowering plants. Nineteenth century naturalist A.R. Wallace, noting that eastern and western Malesia have distinctly different animal species, demarcated a sharp boundary line, "Wallace's Line," to divide the region's flora and fauna. There is a sharp floristic change between Borneo and Sulawesi, which fall between the line, though there is less variation in the Lesser Sunda Islands.
The forests of Southeast Asia can be broadly divided by broad climatic parameters that reflect the amount and seasonal distribution of rainfall. On a more localized, landscape scale, important factors determining forest type and composition include soil moisture, soil type, latitude, and elevation. Whitmore broadly divides tropical forests into those that are seasonally dry and those that are ever wet, or perhumid. Seasonally dry forests with extended annual water shortages are considered monsoon forests, while those with slight annual shortages are often known as semi-evergreen rain forests. In the perhumid regions, forests are broadly divided between those on dry land and those with at least periodically high water tables. Perhumid forests with well-drained soils are further classified as lowland evergreen rain forests, lower montane rain forest, and upper montane forests, sometimes also referred to as "mossy" or "cloud" forests. In areas prone to flooding, forest types include mangrove, which exist along coastal areas exposed to salt water, and freshwater swamp and peat swamp forests (see Figure 4).
Peter Ashton's zonal classification for lowland forests of tropical Asia is climate-based. Broad categories include: wet aseasonal evergreen with no distinctive dry season, wet seasonal evergreen with 2 to 4 months dry season and dry seasonal evergreen with 4 to 6 months of dry season. Most evergreen forests in Southeast Asia are dominated by Dipterocarp species. As an alternative to monsoon forests, Ashton suggests a mixed deciduous category with more than 5 months dry period, and a dry deciduous forest with 7 months or more dry season. These latter zones are subject to seasonal bums and are dominated by fire-tolerant species. (
Note 5)
Tropical lowland evergreen rain forests are found in South America, Africa, and Asia and result from a combination of high and even temperatures, high humidity, and high rainfall. Tall trees, a large volume of biomass, and high species-diversity are characteristic of lowland rain forest vegetation. Rain forests in Southeast Asia are especially rich in species. Study sites in Borneo possess between 200 and 250 species per hectare, versus 50 to 100 species in comparable studies from Africa and tropical America. In the past, the private sector has focused on a narrow range of Dipterocarp and Shorea trees that possess commercial value as timber. For this reason, lowland Southeast Asia rain forests are often referred to as mixed dipterocarp forests. Dipterocarp form the dominant skeleton or structure of the rain forest.
Due to the dense canopy, much of the available sunlight is filtered out before it reaches the forest floor and, as a result, much of the green plant matter is found some distance above the ground. With a multi-tiered structure extending from the forest floor to 70 meters or more in height, Southeast Asian rain forests possess rich biodiversity. Tropical rain forests are often referred to as evergreen forests, though they vary considerably in moisture levels. Rain forests with greater moisture are found largely on the Malay Peninsula, the eastern Philippines, and the islands of Sumatra and Borneo, with scattered patches on the mainland. Typically, rain forests are the natural climax vegetation, or last stage, found in areas where there is less than four months dry season and a minimum of 100 mm. Of Precipitation each wet month. Areas with longer dry Periods are commonly referred to as monsoon forests. Along the margins of rain forests and monsoon forests, a variety of ecosystems shaped by local soil conditions and human activities can be found.
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This lowland rain forest is situated at the base of the Sierra Madre Mountains of Luzon, Philippines, and is home to Dumagat people who travel through the densely forested range to collect rattan. (photo: Poffenberger) |
High levels of Precipitation result in rapid nutrient leaching in rain forest soils. In response, rain forests have evolved tight systems of nutrient recycling relying on efficient decomposition and re-absorption of nutrients. Although plant diversity and biomass volumes are extremely high in Southeast Asian evergreen forests, rain forests possess fewer animals per kilogram of plant matter than any other tropical ecosystems (
Note 6). Animal populations are largely made up of invertebrates, with vertebrates mainly confined to arboreal and flying animals able to take advantage of the food available in the upper canopy stories. While animal Populations increase in the seasonal and monsoon forests in Southeast Asia, these forests do not possess the larger herds of grazing ungulates found in the seasonal and dry tropics of Africa. Instead, animals in rain forests generally are solitary or exist in small family groups. There are exceptions, however, such as the Borneo pig, Sus barbatus, which migrates in large herds during seasonal mast fruiting.Human populations have typically resided in rain forests in small groups, of extended families or clans. In contrast to agricultural communities in Southeast Asia that became alienated from forest environments over the centuries, forest-dwelling communities have remained dependent on forests for wild animal protein, starch from wild yams and palm pith, medicinal substances, resins, fibers and timber, and other products for trade goods.
There is mounting evidence that human beings have manipulated some rain forests in the seasonal tropics for hundreds of years through shifting cultivation and burning, affecting species composition. The fragility of the rain forest environment makes it a challenging context for human habitation. When opened for agriculture, the efficient forest-nutrient cycling system is disturbed, exposing soils to erosion and rapid degradation, especially the organic matter that is the main nutrient store.
Over the millennia, human populations have developed management systems to utilize fragile rain forests for agriculture. These indigenous systems affect the forest ecosystems in different ways, depending on a variety of factors such as site conditions, fire use, length of rotation, and local knowledge. While little longitudinal data is available, Jeff Fox's analysis of time series data from northeastern Cambodia indicates that the long-rotation swidden systems have maintained a dynamic but stable forest cover for the 50 years that the images document (
see Part IV, Box 4). While some shifting cultivation systems have brought about extensive deforestation, Benuaq Dayak forest farmers in eastern Kalimantan are careful to only utilize their swidden fields for one year for their rainfed paddy crop, mixing rattan and fruit trees in the newly regenerating forest after the plot is fallow. The Dayak of Muara Wahau estimate that a young secondary forest takes 3 to 15 years to mature followed by an old secondary forest, and eventually a primary forest in 110 to 180 years, depending on soil conditions. Most of the actively farmed forestland is under a 15-to 50-year cycle. As with many other farmers employing swidden systems, the Benquaq Dayak rarely open primary forest, relying primarily on reopening secondary growth (Note 7).Many forest groups in Southeast Asia have acquired an extensive knowledge of plant use, soil conditions, fire practices, and forest succession patterns, using this knowledge to adapt swidden-farming systems to the surrounding environment. Myth, ritual, taboo, divination rites, and oral traditions, together with communal institutions and leadership, provide a means for implementing forest management strategies and communicating this information across generations. Indigenous knowledge of forest environments, accumulated through centuries of experimentation, allows communities to better regulate forest use and enhance the stability of human-ecological relationships.
Swidden farming systems are suited to low population densities and extensive use practices. As populations increase, both through natural growth and migration, forest farmers are often forced to accelerate their rotations, which leads to depletion of soil nutrients and poor succession rates in fallow areas. Migrant communities settling near the forest frequently lack the traditional knowledge of local residents whose ancestors have resided in the area for generations. Migrants have been responsible for opening millions of hectares of forestland in Southeast Asia, often entering by logging roads and exploiting lands already felled by timber companies. While sustainable management options are limited in the generally poor soils of lowland rain forests, many local forest communities, both migrant and indigenous, are continuing to experiment with new ways to productively manage natural forests. The case studies presented in this report document a diversity of forestry and agroforestry practices that mimic natural rain forests in many ways, including swidden systems, mixed-tropical fruit gardens, damar reserves, rattan groves, and yang oil forests.
Swamp forests exist in areas with water-saturated soils. Found in the coastal regions of Sumatra, Malaya, Borneo and western New Guinea, these forests often occupy areas once covered by mangrove forests. As organic matter accumulates under anaerobic waterlogged conditions and levees develop that reduce salt-water intrusion, inland species begin to replace mangroves. The soil is so anaerobic that bacteria cannot convert fallen vegetable matter into humus. This litter is then converted into peat, which continues to build up over time. As the humus accumulates, the water table changes and different forest species gain dominance. In one site in Sarawak, a peat dome stretching across 20 kilometers of swamp was found to possess six different forest types, located in concentric rings. Soil core samples from the oldest forest in the center of the dome indicate that these six forest types succeeded one another. The inner type is a stunted open forest, with the outer forest comprising commercial species with a height of 50 meters. (
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Fresh water swamp forests like this one located along a Mekong River tributary in southern Laos are an important source of fish and other aquatic foods, as well as fruit and fuelwood. (photo: Poffenberger) |
Since the peat is semi-liquid and nutrient poor, deep peat soils make very poor agricultural land. Where peat swamp forests have been cleared for cultivation, acidic subsoils gradually work their way to the surface after several years of farming, with resulting rapid fertile declines. The Buginese and other ethnic groups in Southeast Asia developed methods of farming rice on these soils for three to five years, while building up "bunds," or mounds, for planting fruit tree crops. As rice fertility declined due to the mixing of acid subsoils, production was shifted to the elevated fruit tree gardens. The Dutch colonial government, and later the government of Indonesia with World Bank funding in the 1970s and '80s, followed an alternative approach in making swamp forests fit for agricultural production. The strategy relied on the construction of networks of drainage canals. Agricultural settlers struggle to sustain agricultural production on acidic soils while large areas in south Kalimantan and other Indonesian provinces have been cleared and drained (
Note 9).Aside from the more brackish peat swamp forests along the coast, there are also a variety of periodically flooded fresh water forests in Southeast Asia. In Borneo, where the water first reaches the flat land after leaving the hills, flood levels can be extreme. An important species in these forest is the ironwood tree (Eusideroxylon zwageri), a heavy hardwood species. Due to its extreme density, ironwood is highly resistant to rot, decay, and insect attack and is therefore prized as material for house posts and shingles. While the houses in these areas literally rot, their ironwood posts can be used for several generations of homes.
One of the largest seasonal swamp forests in mainland Southeast Asia borders Tonle Sap Lake in central Cambodia. During the monsoon season (May through October) water flowing down the Mekong River backs up a tributary, pushing water into the forests surrounding Tonle Sap, the biggest freshwater lake in Southeast Asia. A slight incline in the central Cambodian Depression forces the Mekong to reverse its flow up the 80-kilometer long Tonle Sap channel. The lake level rises 10 to 15 meters during the rainy season covering a 20 to 25 kilometer ring of forests around the lake or some 1500 square miles of land area. Over 200 species of fish migrate into the flooded forest to spawn during the rainy season, feeding off plants and insects that live in sub-merged trees. The government of Cambodia grants fishing concessions for inundated forest areas, including forest ranges flooded during the monsoon. During the dry season, migrants move into communities near the lake. Mining and the conversion of flood forests to agricultural land threaten the complex relations between the lake and river hydrology and the flood forest ecosystem. Commercial timber operations in upstream watersheds have accelerated the sedimentation of Tonle Sap Lake, threatening the fishery that has seen catches fall from over 100,000 tons per year in 1975 to 60,000 tons in the early 1990s. (
Note 10)
Mangrove forests are located in coastal areas, usually in shallow shorelines where silt is deposited by streams and accumulates with the movement of the sea. The spidery roots of the mangroves hold the sediments in place, providing an important habitat for fish fry and other aquatic animals. Mangrove forests once covered much of the shoreline along the Java Sea and the Straits of Malacca. At the outlets of the Solo and Cimanuk rivers in Java, sediment can extend the deltas more than 100 meters each year. The Mekong and Irrawaddy may lengthen 60 to 80 yards annually, creating growing environments for mangroves. (
Note 11)Mangrove forests have less species diversity than other Southeast Asian forest ecosystems. They are largely dominated by Rhizophoraceae species that have the capacity to send down special breathing roots from their branches to capture oxygen from the air. As the roots trap silt, they gradually create a firmer and drier environment. The pioneering genus, Sonneratia, establishes itself above the level of the lowest of the low tides. Its tolerance for salt water allows it to withstand almost continuous inundation. The Sonneratia creates a forward wall and through its web-like root system traps silt, building a shallower base for the species of the Rhizophora genus. In turn, species from the Bruguiera genus of mangrove are able to colonize land higher up the bank, where its more sensitive roots are washed only in the highest of tides. Mangroves are able to colonize the silting deltas of the large Southeast Asian rivers possessing some 30 species with special features that allow them to exploit each phase of land creation. Some species reach heights of 30 meters or more, while others are low and shrub-like. The seeds of the mangrove germinate before leaving the parent tree and are ready to take root when they fall into the mud. They are also able to float with the tide for extended periods until they reach a suitable growing site. Along the western coast of the Malay Peninsula, mangrove forests form a fringe up to 12 miles wide. Moving inland, mangrove is replaced by the nipa palm and pandanus.
Mangrove forests like these young regenerating stands on the coast of Cebu in the Philippines
send their spidery roots down to hold the sediment, providing a safer haven for fish fry, crabs,
and other animals. (photo: Poffenberger)
Mangrove forests in Southeast Asia are being cleared at a rapid rate, more quickly than other natural forest ecosystems. Because these forests are well suited to producing tiger prawns and shrimp, large capital investors have been gaining control over them and converting them for commercial aquaculture. In some parts of the region, local communities have struggled to retain control. In southern Thailand, one survey found 110 coastal communities protecting over 100 patches of mangrove and peat/swamp forests. In only two cases were these communities traditional forest protection groups, the vast majority having been formed since the late 1980s to resist both external and internal encroachments on the resource base (
Note 12). Along the northern coast of Java, shrimp and prawn culture developers and charcoal producers have cleared much of the mangrove forests that buffered the shoreline. In the late 1980s the State Forest Corporation attempted to conserve some of the remaining mangrove forest by empowering local communities to act as managers of aquaforestry groves that combined mangrove trees on bunds with fish farming in brackish water ponds interspersed in the forest.Despite community and government efforts to conserve coastal mangrove forests in Southeast Asia, the ecosystems are disappearing rapidly. Throughout most of the 1980s and 1990s, Indonesia lost an estimated 100,000 hectares annually, representing a two percent decline of mangrove forests each year. In Thailand, nearly two-thirds of the nation's mangrove forests have been degraded through heavy fuelwood and timber exploitation, with a total annual loss of 2,700 hectares. Mangrove forests in Vietnam were severely damaged during 1960s and '70s, with about one-half destroyed through aerial spraying of the herbicide Agent Orange by the American military. A Vietnamese government initiative to re-establish mangrove forests has led to an impressive recovery of these coastal forests in parts of the Mekong and Red River deltas. Scientists are concerned that the reduction in mangrove forests throughout Southeast Asia, while benefiting prawn and fish farmers, has been done at a considerable cost to sea fishermen who have lost a critical spawning ground for future catches.
Monsoon forests, also termed tropical deciduous forests according to classification systems developed by H. Champion and Peter Ashton, are quite distinctive in the dry season when their predominantly deciduous trees shed their leaves. Rainfall in these drier forests usually ranges from 700 to 2,000 mm. annually, versus 2,000 to 4,000 mm. of precipitation per year in lowland rain forests. A more powerful indicator of forest type than total rainfall, however, is seasonality. In the wet season, without careful study of the structure, species composition, and related features, many tropical deciduous forests are difficult to distinguish from evergreen forests. Since rain forests and monsoon forests are difficult to distinguish in satellite images and aerial photographs, they are often classified together as closed or moist forests. Typically, monsoon forests are found in regions with a regular dry season of five months or more and with less than 60 mm. of precipitation. Longer dry seasons are often associated with decreased canopy density, reduced species diversity, and shorter forest stature.
Tropical deciduous forests or monsoon forests are distinctive in the dry season when they shed their leaves.
This regeneratings stand of deciduous trees is located in Takeo Province in Cambodia
(photo: Poffenberger)
Dry deciduous lowland monsoon forests [of north and northeast Thailand and Burma are well known for their teak (Tectona grandis), a valuable species of timber. Teak withstands extended dry seasons and grows best in well-drained, dry subsoils high in calcium. In the dry deciduous dipterocarp forests in the lower hills of northern Thailand, trees of the Shorea and Melanorrhoea genera are common. Monsoon forests are more prone to burning than rain forests, and are actually dependent on fire for regeneration. The lowland monsoon mixed deciduous forest is shorter in stature than the lowland rain forest, with some trees attaining heights of around 20 meters. They may also possess denser understories of four or five tiers. Bamboo often forms dense thickets.
In mainland Southeast Asian countries monsoon forests make up between 15 and 30 percent of the forest cover. Extensive tracts of monsoon forests have been converted to agricultural land over the past 50 years, because of their relatively fertile soils. In northeastern Thailand, forest cover fell from 50 percent of the area in 1953 to 13 percent in 1991, much of it monsoon forest. Deforestation has been driven by an increase in population that ranged from 3.3 to 3.8 percent annually during the 1960s and '70s. Growing numbers of local and migrant peoples cleared the forest to plant commercial field crops like hemp and cassava that required large tracts of land. Teak, an important species in many mainland Southeast Asian monsoon forests, has been heavily exploited for its value in house construction. As a consequence, monsoon forests are subject to commercial logging pressures.
Insular and mainland Southeast Asia possess a wide range of mountain forest types including higher elevation montane and a variety of lower elevation hill forests. Latitudinal regions range from tropical, through warm tropical, to cool temperate, verging on alpine in the higher elevations of Irian Jaya. Most montane forests in Southeast Asia, however, are either lower montane tropical evergreen or upper montane mossy forest. Montane forests, particularly mossy forests, play an important hydrological and biological conservation role. When located on steep slopes with highly organic soils in high rainfall areas, cloud forests protect the watershed against erosion. Deforestation in such contexts often leads to catastrophic landslides. (
Note 13)Montane forests are characterized by the presence of a diversity of ferns, mosses, gingibers, and orchids. Trees are often stunted and gnarled with a smooth, low canopy. Moisture levels tend to be higher than neighboring forests at lower elevations as they are augmented by fog and cloud humidity. Upper montane cloud forests in Southeast Asia are typically found to be between 1,500 and 3,500 meters. Lower montane rain and monsoon forests usually fall within the range of 1,000 to 2,000 meters. Montane forests are important reservoirs of endemic species, especially birds. Above 3,500 meters can be found subalpine and alpine forests. As lowland forests have diminished, mammal populations have also moved into more mountainous areas with forest cover.
Lower montane forests below the cloud line are drier, especially those along the coastal ridgelines that are subject to trade winds. Lower elevation forests above the cloud base possess emergents and are subject to greater precipitation. The boundary between lower and upper montane forests is often distinctive, with a narrow blending zone (ecotone). (
Note 14) Upper montane forests normally begin at the bottom of the zone where clouds usually form. The habitually moist environment creates a sodden, anaerobic condition where litter decomposition is slow. As a consequence, it has similarities to both the peat swamp and heath forests. Due to the lengthy process of decomposition, nutrients remain locked in the forest litter and unavailable to plants. (Note 15) Because montane forests can "strip" water from clouds and maintain low evapo-transpiration water "loss," these mossy forests play an important role in capturing and filtering water into surface and ground water. This type of forest is particularly important on smaller islands, where montane forests are crucial for sustaining water supplies.
This montane forest is located on the slopes of Mount Agung on the island of Bali at an elevation of
approximately 2,000 meters. The forest is recovering from damage occurring during past volcanic eruptions.
(photo: Poffenberger)
In recognition of the environmental service these types of forests provide, they have often been protected from felling by indigenous cultures, especially when situated in the upper catchments of important springs and streams. Lower montane forests, with some of the most humus-rich, non-acidic soils in the region have experienced immense pressure from lowland migrants. Upper montane forests with better soils are being cleared for the cultivation of European vegetable crops, which thrive in the moist, cool climate. Some of the more remote, higher-elevation montane forests in Southeast Asia have experienced fewer disturbances than lowland forests. For example, in the Philippines most of the remaining old growth, which covers less than one percent of the land area, is mossy, upper montane forest.
The relatively better condition of some mountain forests is attributable to their inaccessibility, as well as to the lesser abundance of commercial timber species. But, expanding local populations that depend on mountain forests for fuelwood have put these forests at risk in recent decades. Perhaps more threatening has been the expansion of roads into mountainous regions and, with them, commercial development. In northern Thailand, upland Java and Sumatra, and through much of the upper watersheds of the Philippines, montane forests have become increasingly fragmented in recent years. At the same time, because of the unique characteristics of these environments, they have immense potential for nature conservation and ecotourism.
1 Karl L. Hutterer, "People and Nature in the Tropics" in Karl L. Hutterer, A. Terry Rambo, and George Lovelace (eds.), Cultural Values and Human Ecology in Southeast Asia (Ann Arbor: CSEAS, University of Michigan, 1985) p. 60.
2 T.C. Whitmore, An Introduction to Tropical Rain Forests (Oxford: Clarendon Press, 1990) p. 29.
4 N. Mark Collins, Jeffrey A. Sayer and Timothy C. Whitmore, The Conservation of Tropical Forests: Asia and the Pacific (New York: Simon and Schuster, 1995) p. 9.
5 For an excellent summary of regional forest classification systems in Asia, see Peter Ashton, "Towards a Regional Forest Classification for the Humid Tropics of Asia," in E.O. Box et al. (eds.), Vegetation Science in Forestry (Netherlands: Kluwer Academic Publishers, 1995) pp. 453-464.
6 Hutterer, p. 62.
7 Mark Poffenberger and Betsy McGean, Communities and Forest Management in East Kalimantan: Pathway to Environmental Stability (Berkeley, USA: Asia Forest Network, 1993) Research Network Report Number 3, pp. 16-32.
8 Whitmore, p. 22.
9 KEPAS, Tidal Swamp Agro-Ecosystems of Southern Kalimantan (Jakarta, Ministry of Agriculture, 1983).
10 Jacqueline Desbarats, Prolific Survivors: Population Change in Cambodia, 1975-1993 (Tempe, Arizona: Arizona State University, 1995) p. 16-21.
11 S. Dillon Ripley, The Land and Wildlife of Tropical Asia (New York: Time Incorporated, 1964) p. 81.
12 Nitin Rittibhonbhun, "Community-Based Forest Management in Southern Thailand," Community Forestry Case Study Series, CM004/95, (Bangkok: RECOFTC and AFN, 1995) p. 4.
13 Lawrence S. Hamilton et al., Tropical Montane Cloud Forests: Proceedings of an International Symposium (Honolulu, East West Center, 1993) p. 1, and personal communication from Peter Ashton, April 1999.
