Ratanakiri is a province in the northeast of Cambodia. It has a total land area of 12,500 square kilometers, in which forestland is estimated to be 70-80%, making it an area of great economic potential on account of its natural resources. This region, where the majority of populations are indigenous, traditional swidden agriculture and Non-Timber Forest Products (NTFPs) collection is practiced widely. However, without survey data associated with environmental and social monitoring, much of the level practice may be unsustainable either from the view of a traditional conservation based perspective or modern technique of sustainable practice, since much of the social, economic and political climate is changing. As a result, updating and understanding the contemporary traditional resource management and the trends in both human behavior and practice is crucial, because that understanding is among the important aspects that might be central to the success of traditional community forest management. This study revealed that indigenous populations are practicing resource management instinctively. Moreover, the research showed that recent changes in the social, physical and economic environment affected indigenous people's ability and their behavior from the way they perceive their current livelihood situation to the way they use their natural surroundings. From the fieldwork data, we finally identified strengths, weaknesses, threats and opportunities in the current local knowledge and behavioral change in Yak Poey.

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Global warming due to increase in the atmospheric carbon dioxide level is a matter of growing concern and the carbon-absorbing function of the forest is now an issue gathering public attention. Under such conditions, it is necessary to calculate carbon stock in tree stems, and understand the details of the bulk density of sterns. The aim of this study is to estimate the carbon stock in the forest with guaranteed accuracy by stem analysis and soft X-ray densitometry, using a Stem Density Analyzer (SDA). Samples of beech (Fagus crenata) were collected at Kaminagawa Experimental Forest, Yamagata University. Ten trees were selected from the standing trees in the investigation area. The wood disks were obtained from the stem at a 1-m interval starting from the height of 0.2m. From each disk, four blocks were cut out in the four directions, and a 1.4-mm-thick strip was prepared from each block using a double-toothed circular saw. Annual ring width and bulk density were measured by soft X-ray densitometry. Each 1-m-long stem segment was regarded as a cone trapezoid, and using the average of annual ring widths in four directions, wood volume for each year was calculated. The calculated value was multiplied by average of bulk density to obtain wood dry weight for each year, and it was converted to carbon stock by multiplying by the rate of carbon. SDA was used for these calculations. The distribution of bulk density in the stem was variable in the same individual, and even the average bulk density of each individual varied with the individual, even though the bulk density was measured for the individuals with similar ages and under similar environmental conditions. These results indicate that the examination of bulk density is important for the calculation of carbon stocks. The diameter at breast height (DBH) of trees was found to have a close correlation with the carbon stock. Therefore, we estimated carbon stock per unit area using the correlation formula between DBH and carbon stock in each tree in the investigation area. The estimated carbon stock per unit area in the stand was 44% greater than that estimated by the method currently proposed by IPCC method. Carbon stock can be estimated with high accuracy using the correlation formula between DBH and carbon stock.

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A diameter-distribution prediction system (DDPS) was previously developed for pure even-aged hinoki (Chamaecyparis obtusa Sieb.) plantation. In this study, we examined the applicability of this DDPS to sugi (Cryptomeria japonica D. Don) plantation. We estimated the parameters for the DDPS mainly using a data set obtained from permanent sample plots in western Japan and validated the parameters using a data set obtained from permanent sample plots in the Kanto and Kinki regions. We also compared predicted and observed diameter distributions. We found that when the length of the prediction period was shorter than 16 years and initial stand age was larger than or equal to 31 yr, the predicted and observed density and basal area were not significantly different. The difference between predicted and observed distributions were minor and the goodness of fit appeared sufficient to allow this method to be used for prediction of sugi stand variables and diameter distributions for stands aged over 30 years. Considering the independency of the two data sets used for parameter prediction and validation, it is concluded that the DDPS would accurately predict stand growth in other regions.

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The objective of this study was to elucidate the relationships between canopy tree and forest floor vegetation characteristics, and the fecal pellet-group distribution of a Japanese serow population, in lowland managed forests of Iwate Prefecture in northern Japan. The study area was classified into five forest types: Japanese red pine (JRP), Japanese cedar (JC), other conifers (OC), a mixture of conifer and broad-leaved trees (MCB), and deciduous broad-leaved trees (DBL). Fecal pellet-groups throughout the study area were counted during November/December 2002. Between June and September 2002, the forest vegetation was surveyed using plot inventory in the largest forest block of the study area. One hundred and thirty-eight 100-m² circular plots were established in the forest at the same time. The observed numbers of pellet-groups in the JRP and DBL forests were significantly lower than the left-tail threshold of the expected random distributions generated by a Monte Carlo simulation. In contrast, the observed numbers of pellet-groups in the JC and OC forests were significantly higher than the right-tail threshold of the expected random distributions. These results indicate that the serow used the JC forests frequently for defecation sites, and that the DBL and JRP forests were not used in proportion to their areas. We propose that serows make selective use of JC stands because of reduced forest floor vegetation in these plantations. Coverage by the major component of the forest floor vegetation, dwarf bamboo, is likely reduced in the JC forests by the removal of ground cover vegetation before thinning and by the shady conditions beneath the canopy, which result from canopy tree characteristics.

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