The diversity of trees in Kalimantan is discussed from vegetational data of 50 plots (17.5 ha in total) in Kalimantan and Java. The lowland dipterocarp forest had higher diversity than mountain and secondary forests. West Kalimantan seemed to have richer flora than East. Common species of two plots near to each other in the same vegetation type was 50 to 70 % of total species, and that of two plots in different provinces was several percent. The reason of this is discussed from species area relationships.
The diversity in the ecological functions was considered from data of wind dispersal fruits and specific gravity of woods. Dipterocarpaceae makes wind and non-wind dispersal fruits with long and short sepals, respectively. Both types had great varieties in size. The length of wing of Shorea had wider variety than length of wind-dispersed fruits of Acer which is common in Japanese temperate forests. Shorea also had a wide variety in specific gravity of wood. These varieties may contribute to the dominance of this genus in Asian tropical forests. The variance of 286 species in wood specific gravity in West Kalimantan had wider than in a temperate forest. These varieties in ecological function may be one of the reasons for the coexistence of many species in tropical rain forests.

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Dense haze caused by the forest fire and the slash-and-burn method of agriculture covered a wide area of Southeast Asia in summer and autumn, 1997. The dense haze impacted on not only human health and social activities but also the ecosystem there. Ground water level in a peat swamp forest and solar radiation in open areas were Ineasured in Central Kalimantan from September 1993 to December 1997. The ground water level dropped remarkably to 98 cm below the ground surface because of small rainfall from July to September in 1997. Solar radiation also decreased to about 40 % of normal condition in September. Daily evapotranspiration from the peat swamp forest was estimated from the hourly data of ground water level in the forest. The evapotranspiration showed a linear regression with daily total solar radiation. From this regression, evapotranspiration in September 1997 was estimated to be around 50 % of that in normal condition of 3-4 mm/day. Using this relationship between evapotranspiration and daily change of ground water level, it was estimeted that the dense haze depressed the evapotranspiration of the forest to around 50 % of normal year at the end of September, 1997.

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Borneo is the third biggest island in the world. It is under the tropical rain forest climate and most of the land is covered with lowland dipterocarp forests, where soil properties are mainly determined by the parent materials (Tertiary sand stone and shale) and topography. The red yellow podzolic soils by the Malaysian soil taxononly, Acrisols by the FAO-UNESCO classification, or UItisols by the US soil taxononly are widely distributed on the hilly land, while peat soils and alluvial soils are distributed in the lowland. Some arenacious soils are found in between hills and lowlands, where white coarse silicious sands are accunlulated (kerangas) and hold the kerangas or heath forests.
Soil nutrients in the forest soils were not always partialized on the surface soils as was often pointed out for the tropical forest soils. The rate of nutrient partition to the surface soils (5 cm / 70 cm) is almost equivalent to those found in the temperate forest soils of Japan. Land use capability is mostly determined by the slopes and subdivided by the soil acidity.
The shifting cultivation is one of the nlajor agricultural practices in Borneo island. Compared with the oil palm plantation and pepper field, rice cultivation on the sloping land without any plowing causes less soil erosion. Thus, sustainability of shifting cultivation is more than that of oil palm and pepper cultivation. However, considering the cash crop cultivation of the local people, a well organized agroforestry system should be introduced to protect against the severe soil degradation on the sloping lands.

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Borneo is the third largest island located in the middle of insular southeast Asia. Although the highest mountain is over 4000 m (Mt. Kinabalu), most of the central mountain ranges are below 3000 m. From these medium size mountains, several medium size rivers are flowing down to the surrounding maritime world. Since the river size is optimum for the human scale, river has been the most important route between forest and sea.
This physical situation is important to understand the eco-resources extraction of this island. Different from Africa or South America, rich resources of the island have been easily sent to outer world through rivers and maritime trade routes. The widest exploitation has been carried out in the mixed dipterocarp forest first and now the peat swanlp forests are being opened for plantation or other land uses. The way of this development always comes with wide scale exploitation by many people with heavy machines by the big budget of large companies.
On the other hand, traditional way of living by the local people supports the non-timber resources trade like aloeswood for many years. Their attitude toward resources differs much from the modern wide scale destructive way. They think the resources as a part of ecosystem which should be treated carefully and sustainablly managed.
In this paper, I am focusing on “eco-resources” concept and want to develop this term for future resource management.
“Eco-resources” are not a single biological resource but mixture of several resources in the ecosystem. Without sustainable management of ecosystem, the resources in the ecosystem could not survive. Starting from this simple fact, several examples of “eco-resources” are discussed including several ecosystem exploitation, eco-tourism and forest fire. As a conclusion, shifting people along the resources in the ecosystem contribute to stabilize the community.

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Borneo is in the hunlid tropics, but there have been periodic long and severe dry spells since the prehistoric era, especially in eastern part of the Island. The dry spells usually related to EI Niño Southern Oscillation (ENSO) events. Two of the world’s largest forest fires, occurred in 1982-83 and 1997-98, during severe droughts related to strong ENSO events. Both of the fires affected about 5 million hectares of land ares in eastern part of the Island. The recent increase in human activities as well as extent of grassland led to extensive and repeated wildfires during the dry spells. The damage in the 1982-83 fires was greater in logged-over secondary forests than in primary forests. After the fire, the severely burned forests were dominated by pioneer tree species; growth of Macaranga triloba and Macaranga gigantea was definitely promoted by the fire. The 14-year interval between the large wildfires in 1982-83 and 1997-98 was not sufficient for forest recovery. Subsequently, tree mortality in 1997-98 fires was higher in the stands where the logging intensity and fire disturbance in the past were high. In order to conserve the remaining forests and to rehabilitate the burned forests, the occurrence of forest fires must be diminished.

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Kalimantan is in a process of transition frOl1l an economy based on natural resources extraction (mostly logging on natural forests) to an economy evolved around large-scale plantation. In the literature on tropical deforestation, there is some tendency not to distinguish timber extraction and land development for considering their impacts on the environlnent and society. In this paper, I will try to use the concept of two types of frontier formation, which are timber extractive frontier and land development frontier, for explaining the characteristics of the past and on-going regional transformation and its inlpacts on the forest environnlent and local cOlnnlunities in inland Kalimantan.
There are clear differences in characteristics between timber extraction and plantation. The existing tilnber extraction from natural forests is based on selective logging of commercial timber, while the plantation development is based on land development which requires clear-felling of trees and removing of tree roots. The differences in production characteristics of the two frontier economies have different kinds of impacts on the forest environment and local communities. The forest destruction in the age of road and land development tends to be nlore widespread and of higher speed than that in the age of river transport and timber extraction.

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