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Sihanoukville, Cambodia

Toyama H.,Kyushu University | Kajisa T.,Kyushu University | Tagane S.,Kyushu University | Mase K.,Kyushu University | And 8 more authors.
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2015

Ecological communities including tropical rainforest are rapidly changing under various disturbances caused by increasing human activities. Recently in Cambodia, illegal logging and clear-felling for agriculture have been increasing. Here, we study the effects of logging, mortality and recruitment of plot trees on phylogenetic community structure in 32 plots in Kampong Thom, Cambodia. Each plot was 0.25 ha; 28 plots were established in primary evergreen forests and four were established in secondary dry deciduous forests. Measurements were made in 1998, 2000, 2004 and 2010, and logging, recruitment and mortality of each tree were recorded. We estimated phylogeny using rbcL and matK gene sequences and quantified phylogenetic a and b diversity. Within communities, logging decreased phylogenetic diversity, and increased overall phylogenetic clustering and terminal phylogenetic evenness. Between communities, logging increased phylogenetic similarity between evergreen and deciduous plots. On the other hand, recruitment had opposite effects both within and between communities. The observed patterns can be explained by environmental homogenization under logging. Logging is biased to particular species and larger diameter at breast height, and forest patrol has been effective in decreasing logging. © 2015 The Author(s) Published by the Royal Society. All rights reserved. Source

Sasaki N.,University of Hyogo | Chheng K.,Forestry Administration | Ty S.,Ministry of Agriculture
Environmental Science and Policy | Year: 2012

Sustainable forest management (SFM) ensures the continuous flow of wood products and employment while improving the functionalities of forests as compared to conventional management. Until recently, many projects associated with the reducing emissions from deforestation and forest degradation (REDD) scheme focused only on reducing emissions from deforestation and forest degradation, conservation of carbon stocks, or enhancement of forest carbon stocks. REDD+ is an extension of REDD that also includes, SFM, conservation of carbon stocks, and enhancement of forest carbon stocks. REDD+ projects concerned with securing timber production while reducing emissions are very few in number. In this report, we discuss how SFM through the adoption of appropriate logging practices can lead to a reduction in carbon emissions while securing timber in the tropics. Logging practices affect timber production, the structure of forests, and forest-dependent communities because of damages caused by logging itself and the large amounts of logging and wood wastes. By switching from conventional logging to reduced-impact logging practices, International Tropical Timber Organization producer countries could reduce carbon emissions by about 1.5-2.1billion tCO 2year -1 while still producing about 164.9-280.8million m 3 of end-use wood under a 50-year project cycle, with the results being dependent on the chosen scenario. Study results suggest that a policy of reduced-impact logging combined with a 40-year or longer cutting cycle is appropriate for SFM projects as part of the REDD+ scheme. © 2012 Elsevier Ltd. Source

Zhang M.,Kyushu University | Tagane S.,Kyushu University | Toyama H.,Kyushu University | Kajisa T.,Kyushu University | And 2 more authors.
Ecological Research | Year: 2016

Some previous studies along an elevational gradient on a tropical mountain documented that plant species richness decreases with increasing elevation. However, most of studies did not attempt to standardize the amount of sampling effort. In this paper, we employed a standardized sampling effort to study tree species richness along an elevational gradient on Mt. Bokor, a table-shaped mountain in southwestern Cambodia, and examined relationships between tree species richness and environmental factors. We used two methods to record tree species richness: first, we recorded trees taller than 4 m in 20 uniform plots (5 × 100 m) placed at 266–1048-m elevation; and second, we collected specimens along an elevational gradient from 200 to 1048 m. For both datasets, we applied rarefaction and a Chao1 estimator to standardize the sampling efforts. A generalized linear model (GLM) was used to test the relationship of species richness with elevation. We recorded 308 tree species from 20 plots and 389 tree species from the general collections. Species richness observed in 20 plots had a weak but non-significant correlation with elevation. Species richness estimated by rarefaction or Chao1 from both data sets also showed no significant correlations with elevation. Unlike many previous studies, tree species richness was nearly constant along the elevational gradient of Mt. Bokor where temperature and precipitation are expected to vary. We suggest that the table-shaped landscape of Mt. Bokor, where elevational interval areas do not significantly change between 200 and 900 m, may be a determinant of this constant species richness. © 2016 The Ecological Society of Japan Source

Theilade I.,Copenhagen University | Schmidt L.,Copenhagen University | Chhang P.,Forestry Administration | McDonald J.A.,University of Texas-Pan American
Nordic Journal of Botany | Year: 2011

As part of recent field studies, a hitherto undescribed type of evergreen freshwater swamp forest was discovered in Stung Treng Province, Cambodia. The swamp forest occurs in at least six disjunct localities and is dominated by hydrophytic trees (Eugenia spp., Ficus spp., Litsea spp., Macaranga triloba, Myristica iners and Pternandra caerulescens). Although these same genera also occur in upland forests, most are represented by different species in the swamps. Livistona saribus emerges from the canopy as an indicator species of this vegetation type while dense stands of other palms (Calamus, Areca, Licuala) and sporadic, dense populations of tree ferns (Cibotium barometz) dominate the understory. Pneumatophores, stilt roots, and aerial roots characterize the hydrophytes. The floristic composition indicates that the forest type is distinct compared to other swamp forests described from the region and worthy of protection based on its rarity and ecological uniqueness. © 2011 The Authors. Source

So T.,Forestry Administration | Theilade I.,Copenhagen University | Dell B.,Murdoch University
Pacific Conservation Biology | Year: 2010

The leguminaceous rosewoods, Afzelia xylocarpa (Caesalpiniodeae) and Dalbergia cochinchinensis (Faboideae) are threatened by habitat loss and exploitation for their extremely highly-prized timber throughout their range. This paper examines the current conservation status of A. xylocarpa and D. cochinchinensis in Cambodia, draws together information on silviculture and trade, and summarizes current conservation measures in the country. Urgent measures are required to conserve and sustainably use the remaining genetic resources. Opportunities and challenges for achieving these goals, through use of the two threatened species in reforestation, are discussed. The suitability of the species for reforestation combined with increasing domestic and international prices for rosewood provide an opportunity for promotion of the species in planting programmes. This would not only alleviate the pressure on their natural habitats, but also bring about economic benefit. The paper outlines some important steps in the development of domestication strategies including testing and improving silvicultural practices, and increasing the supply of genetically superior seeds from seed production areas and/or seed orchards. As a first step, a network of in situ gene banks has been established in natural forests in Cambodia. A wide range of stakeholders need to participate in such programmes in order to address socio-economic development and poverty reduction. This is in line with the main objective of the National Forest Programme of Cambodia. Source

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