Project Area 1:
The term Prey Long (or Prey Lang) has been used to refer to the extensive lowland dry evergreen and semi-evergreen forest landscape that is located between the Mekong and Stung Sen Rivers in northern Cambodia. It is centered upon the remnants of the original surface of the ancient alluvial plain that once extended across northern Cambodia but much of which has long been eroded away. This area supports roughly 3,600 square kilometers of forests. It measures roughly 120 km in its north-south axis from Kampong Cham province to the Laos border, and 30km in its east west axis from the Mekong River to the Stung Sen River.
Lowland dry evergreen forests dominate the central portions of the alluvial plain and are associated with the red-yellow podzol soils there. The forest grades through lowland semi-evergreen forest upon the grey hydromorphic soils to dry deciduous forests in more peripheral areas where they are associated with the less productive plinthite podzols and/or shallow lithosols soils.
In addition to the lowland dry evergreen, semi-evergreen and dry deciduous forests, this landscape also features a number of other forest communities. They include mixed dry deciduous forests dominated by Lagestroemia, short riparian and Melaleuca forests, short semi-evergreen forests, deciduous swamp forests and evergreen swamp forests.
Biodiversity Values
This heavily forested landscape has particularly high conservation values and sustainable use of biodiversity. These values stem from:
• The largest of primary lowland dry evergreen forest remaining in both Cambodia and Indochina.
• The existence of the range of critical and fragile habitats including swamp forests may act as repositories of ancient forest lineages.
• The existence of healthy wildlife populations including endangered species such as elephants, gaur, banteng, tiger and Asiatic black bears as well as clouded leopards and rare turtle species.
All of the forest types described here warrant some form of protection. This is particularly true for the lowland dry evergreen forests and the evergreen swamp forests. These forests are rich in biodiversity and refuge rare species. Both of these forest types are quintessentially Cambodian in origin and character. The evergreen swamp forests appear to constitute an endemic forest formation that is endemic to Cambodia.
The lowland dry evergreen forests are distinctive from those on other lowland forests associated with the Cardamom and Elephant Ranges in the south-west, and the southern Annamites in the north east. It is also apparent that these forests maintain a level of biodiversity that equals or exceeds other lowland areas in Cambodia. The biological value of Prey Long seems all the more critical because most the Cambodia’s protected evergreen forests are located in or near mountainous regions (MacDonald 2004). These tall Dipterocarp forests of central Cambodia are of global significance, in that they represent a type of vegetation that was once formerly common throughout the whole of South East Asia but has largely been extirpated from the region.
Lowland dry evergreen forests on alluvial soils, especially those communities on the alluvial soils, have been subject to extensive logging during the last decade and remain particularly vulnerable to future logging. As a result of the extensive nature of these impacts only the core area of the Prey Long forest located within the upper catchments of the Stung Porong and O Long watercourses may be considered to be primary lowland dry evergreen forest (MacDonald 2005). Indeed, this forest now remains the largest patch of primary lowland dry evergreen forest within both Cambodia, and the entire Indochinese floristic province. This area lies within the unlogged portions of the former Colexim and Everbright concessions and was also untouched by logging operations in the 1960s.
The inclusion of roughly 80,000 to 100,000 hectares of unlogged or primary stands of this forest type places particular importance upon this focal area because this forest type has suffered heavy levels of deforestation and degradation throughout its range in the Indo-Chinese floristic province.
These forests are habitat to wide diversity of Cambodia’s vascular plants including 11 threatened tree species and 19 of the 21 species prioritized for genetic conservation by the CTSP; as well as a diverse array of timber species. In addition, the area retains a range of key wildlife species including elephant, gaur, banteng, gibbons and hornbills. Although survey effort in this area is very limited it is already apparent that Prey Long features 16 to 22 threatened mammals, seven to 21 threatened birds and three to seven threatened reptiles.
Ecosystem Services
This forest landscape has particularly high social values. These derive from:
• The large population living either within or peripheral to this landscape.
• Its historical and current role as a provided of non-timber forest products to a large portion of the Cambodian population on a daily basis.
Over 250,000 people live in 339 villages that are largely located within the peripheral areas of this landscape. Villages are generally located along the larger streams and therefore around the periphery of the Prey Long forest although some recent settlements are the targeted areas that were relatively remote until recent years. A further 450,000 people live in 450 villages within ten kilometers of the boundary of this landscape. This landscape has a particular importance as it provides a livelihood for some ethnic minorities, notably the Kouy. It is also of great culture value for the Kouy.
While this area has been a focus for commercial timber extraction in its recent history, its principal utilitarian values appear to lie elsewhere. It has important watershed values. It is apparent that these forests have a broader significance in the water cycle within northern Cambodia as they play a critical role in provoking rains in central Cambodia and in maintaining water in the region throughout the year. Its extensive catchment area and deep soils constitute an important contribution to the maintenance of dry season flows. The role that both the lowland dry evergreen and swamp evergreen forests play in regulating water flows also serves to prevent sedimentation of the Tonle Sap lake.
These waters drain either directly to the Mekong or Stung Sen rivers, or to the Tonle Sap Lake via the Stung Chinit river. Thus, Prey Long contributes substantial waters to the agricultural areas on the floodplain of the Stung Sen River as well as those further downstream. The Stung Chinit river is also of particular importance because it directly supplies downstream agricultural areas in Kampong Thom province that are the focus of development efforts.
Prey Long also has important roles in the provision of non-timber forest products. It is a major source of tree resin within Cambodia. This resin is tapped in traditional manner from the large dipterocarp trees and sold to traders who sell in the domestic or export markets. Much of the resin is directly exported to Vietnam. The semi-evergreen forests are an important and traditional source of commercial bamboo harvests.
Perhaps the least well understood ecosystem service provided by Prey Long is that of carbon sequestration. The lowland dry evergreen forests appear to store more carbon that any other forest type in the country as they have perhaps the highest timber volumes and biomass of Cambodia’s forests when in an undisturbed state. They are therefore of particular importance to the consideration of Cambodia’s GHG emissions. The fact that much of the forest within this landscape has undergone heavy degradation adds additional importance to forest regeneration. If these degraded forest areas are allowed to regenerate this will result in the sequestration of very substantial amounts of carbon.
A Protected Area System Gap Analysis conducted by the World Bank funded Biodiversity and Protected Areas Management Project (BPAMP) has identified the Prey Long forest as one of four areas of highest priority for additional protection measures.
Project Area 2:
Phnom Aural was designated as a Wildlife Sanctuary by the 1993 Royal Decree on Protected Areas, at a time when the area was still contested by Khmer Rouge and government forces. Its designation as a wildlife sanctuary reflected not only its high conservation value, but also the willingness of the government of the time to grant protected status to regions.
Phnom (Mount) Aural, Cambodia’s highest mountain, is a unique granite mountain that sits as an outlier of the main Cardamom Range in south-west Cambodia. This virtually symmetrical mountain represents an ancient volcano that has long been extinct though a few hot water pools persist in its hinterlands. There are relatively few villages in the districts associated with Phnom Aural. Here it tends to be limited to lowland areas associated with the larger streams originating from the mountain. There are no villages on the mountain slopes.
The mountain supports extensive lowland evergreen and sub-montane evergreen forests that are fringed by lowland semi-evergreen forests. Much of the surrounding hinterlands are comprised of the erosion products from the mountain and support deciduous forests and other more degraded vegetation. In recent years these deciduous forests still retained a high diversity of orchid species. The great height of this mountain has produced an altitudinal cline in the vegetation which changes in both structure (physiognomy) and composition as altitude increases. Sub-montane evergreen forests replace lowlands evergreen forests at about 700 masl. These are in turn replaced by shorter dwarf evergreen forests above 1,500 masl.
Biodiversity Values
This vulnerable jewel of the Cardamom Mountains is apparently one of the most biologically diverse sites in the country. It is expected to have a high level of national endemic plant species and still retains a range of key wildlife species including elephant, gaur, banteng, gibbons, and hornbills. These values stem from:
• Its diversity of evergreen forest formations.
• Its high elevation and uniqueness as the only large area of granite within the country.
• The continuity with the extensive forest landscape of the Cardamom Mountains in South-west Cambodia.
Phnom Aural’s sub-montane forests have both a high national and international conservation significance as an important component the wider centre of plant diversity and endemism of the Cardamom Ranges. These ranges are believed to harbour about half of Cambodia’s known 214 endemic plant species as well as a substantial number of regionally endemic species (Dy Phon 1981, Rundel 1999). Furthermore, the dwarf evergreen forests formation growing on the poorer soils at high elevations are an endemic formation restricted to south-west Cambodia (Dy Phon 1981).
All of the forest types described here warrant some form of protection. This is particularly true for the evergreen forests on the mountain slopes. These forests are rich in biodiversity and rare species. The dwarf evergreen swamp forests at higher altitudes appear to constitute a forest formation that is endemic to Cambodia. The lowland deciduous forests receive higher rainfall than those in other parts of the country and so may be richer in plant species diversity. This may be the explanation of their richness in orchids.
Phnom Aural’s forests appear to maintain a level of biodiversity that equals or exceeds other forest areas in Cambodia. This biological value seems all the more critical because most the uniqueness of the area’s geology and the increasing pressures upon its timber. In spite of these pressures, these forests are habitat to wide diversity of Cambodia’s vascular plants: probably more than in the lowland dry evergreen forests described above. Phnom Aural is habitat to between 23 and 33 threatened tree species. Fourteen of the 21 species prioritized for genetic conservation by the CTSP are found in nearby areas within the Cardamom Ranges. In addition, the area retains a range of key wildlife species including elephant, gaur, banteng, Eld's Deer, gibbons and hornbills.
Ecosystem Services
This forest landscape has particularly high social values. These derive from:
• The large population living either within or peripheral to this landscape.
• Its historical and current role as a provided of non-timber forest products to a large portion of the Cambodian population on a daily basis, particularly medicinal plants.
• The regulation of water flows to extensive agricultural areas within Kampong Chhnang, Kampong Speu and Pursat provinces.
While the lowland deciduous and semi-evergreen forests have been a focus for illegal timber extraction in its recent history the principal utilitarian values of Phnom Aural lay elsewhere. Several of the country’s densely populated districts are contiguous with Phnom Aural. These support large populations and have received large numbers of migrants in recent years. Many people from nearby agricultural areas are dependent upon the forests as an economic “safety net” during the dry season. This landscape has a particular importance as it provides a livelihood for some ethnic minorities, notably the Soui. It also includes sacred sites for the Soui, like a hotspring area south of Aural Mountain.
Phnom Aural has important watershed values for surrounding agricultural areas and the proposed dam on Prek Thnout watershed area to the south. It is likely that the forests play a supplementary role to that of the mountain itself in provoking rains in central Cambodia and in maintaining water in the region throughout the year. This extensive forested catchment area makes an important contribution to the maintenance of dry season flows and in reducing sedimentation in lowland areas.
These waters drain either directly to the Mekong River, Prek Thnout River or to the Tonle Sap. The Prek Thnout River is also of particular importance because it directly supplies downstream agricultural areas in Kampong Speu province that are the focus of development efforts.
Phnom Aural also has important roles in the provision of non-timber forest products. It is a major source of medicinal plant trade within Cambodia. A variety of plants are collected by villagers and laborers for both the domestic market and for export. Phnom Aural is one of the main sources for traditional medicines for the large diverse consumer market in Phnom Penh.
Phnom Aural also has an important role in carbon sequestration as it supports extensive evergreen forests. Indeed those at higher elevations are reportedly associated with highly organic soils that may also store substantial carbon reserves. The fact that degradation of forest within this landscape has largely been restricted to lowland deciduous forests augurs well for its carbon sequestration role. Nevertheless, the threat to forests on the mountain slopes have increased in recent years adds additional importance to forest protection. (cited: D. Ashwell et al, 2009)
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