Tropics最新文献

{"title":"Variations of leaf and stem traits in relation to altitudinal distributions of 12 Fagaceae species of Mount Kinabalu, Borneo","authors":"Kiyosada Kawai, Berhaman Ahmad, I. Palle, Naoki Okada","doi":"10.3759/tropics.ms19-14","DOIUrl":"https://doi.org/10.3759/tropics.ms19-14","url":null,"abstract":"Fagaceae in Southeast Asia shows diverse distributions along altitude, but the underlying mechanisms remain unclear. Since species ʼ traits (morphological and physiological characteristics) can dictate their resource use strategies (e.g., the way of resource acquisition and allocation), they potentially influence their distributions along altitude. Here, to examine the linkage between species ʼ traits and altitude, we quantified the variation of 10 leaf and stem traits of 12 Fagaceae species growing in Mount Kinabalu, Borneo and related traits to species ʼ lowest and highest limits and altitudinal range. Species with high leaf dry mass per area (LMA) and lamina thickness showed higher upper limits of altitudinal distribution whereas no traits were correlated with the lower limits. LMA and leaf nitrogen content positively covaried with species ʼ altitudinal range. These results demonstrate that species with conservative resource use had higher altitudinal limits and wider altitudinal range, highlighting the role of leaf traits in the diversification of altitudinal distributions among closely-related species. We further suggest that diversifications in leaf traits potentially lead to the coexistence of Fagaceae species in tropical montane forests.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Smallholder’s labor allocation for livelihood diversification: A case study in an upland village in northern Laos","authors":"Khamphou Phouyyavong, S. Tomita, S. Yokoyama","doi":"10.3759/tropics.ms19-08","DOIUrl":"https://doi.org/10.3759/tropics.ms19-08","url":null,"abstract":"Livelihood diversification involves the well-characterized strategies of smallholder farmers to combine risk aversion under a market economy. Since livelihood diversification studies have focused on diversifying income sources to include non-farm and off-farm income, the benefit of adding subsistence-oriented farming to the livelihood portfolio has been underestimated. This form of livelihood diversification is broadly observable in Southeast Asia, and could be another risk aversion strategy to cope with unpredictable market conditions. This study examined the role of swidden farming in livelihood diversification through the analysis of individuals’ labor allocation in livelihood portfolio, annual working hours, and seasonal changes in working hours in a village in northern Laos. Information was obtained through direct interviews with 133 individuals. Interviews were conducted in 2017 and gathered information on demographic features, economic activities, and monthly working hours for individual in 2016. The results indicated: 1) Individual’s livelihood portfolio was determined by the assets that the ethnic group and each household held to a large extent; 2) Livelihood diversification took place at the individual level rather than at household level, through an increase in annual working hours, as well as monthly working hours during the peak period of labor demand; and 3) Labor demand for swidden farming was moderate, so villagers can incorporate it into their livelihood portfolio. The study highlighted that flexibility would be another facet of livelihood diversification. Swidden farming was likely to play a pivotal role in its flexibility, but it was not important as an income source.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/tropics.ms19-08","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elucidating the phenology of the Sundarbans mangrove forest using 18-year time series of MODIS vegetation indices","authors":"M. S. N. Mandal, M. Kamruzzaman, T. Hosaka","doi":"10.3759/tropics.ms19-11","DOIUrl":"https://doi.org/10.3759/tropics.ms19-11","url":null,"abstract":"Mangrove forests are the most carbon-rich ecosystems in the world however, baseline information on its phenology is poor. Information on seasonal changes in canopy greenness, which reflects the level of photosynthetic activity, is helpful for understanding seasonal patterns of carbon uptake by mangrove forests. To elucidate the periodicity, timing, and length of the active photosynthetic season, we examined temporal patterns in enhanced vegetation index (EVI) and normalized difference vegetation index (NDVI) derived from 18-year (2001 - 2018) Moderate Resolution Imaging Spectroradiometer images for four major forest types in the Sundarbans, Bangladesh. We identified a dominant cycle for the time-series of EVI and NDVI after Fourier transformation. We also estimated four phenological dates among the forest types: the start of the season (SOS), time of maximum greenness (MaxGreen), end of the season (EOS), and length of the season (LOS). Fourier analysis revealed that both the NDVI and EVI exhibited distinct cycles per year for all forest types, suggesting that there are annual cycles of canopy greenness. The SOS as estimated using the EVI and NDVI was consistently from late May to mid-June across forest types. However, the MaxGreen, EOS and LOS estimated varied between the two indices. Because EVI-based phenological dates match better with phenological information at the ground level than do NDVI-based dates, the EVI would be better than the NDVI for depicting changes in canopy greenness. The results of this study provide baseline information for future phenological changes in the Sundarbans.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/tropics.ms19-11","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum to MS19-14","authors":"","doi":"10.3759/tropics.ms19-14err","DOIUrl":"https://doi.org/10.3759/tropics.ms19-14err","url":null,"abstract":"","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wood properties and simulated modulus of elasticity of glulam in three fast-growing tree species grown in community forests in Yogyakarta, Java Island, Indonesia","authors":"A. Ngadianto, F. Ishiguri, I. Nezu, Yusuke Takahashi, J. Tanabe, F. Hidayati, D. Irawati, J. Ohshima, S. Yokota","doi":"10.3759/tropics.ms20-02","DOIUrl":"https://doi.org/10.3759/tropics.ms20-02","url":null,"abstract":"Community forests in Indonesia are important suppliers of wood resources for the wood industry. In the present study, stress-wave velocity of stems, log characteristics (taper, green density, and dynamic Young ʼ s modulus), and wood properties (basic density, compressive strength parallel to grain, modulus of elasticity [MOE], and modulus of rupture [MOR]) were investigated for three fast-growing tree species grown in community forests in Indonesia: Acacia mangium Willd. , Maesopsis eminii Engl. , and Melia azedarach L. Based on the bending properties, the MOE values of laminae (30 × 150 mm in cross-section) and glulam (six layers, 90 × 150 mm in cross-section) were simulated. The mean values of simulated MOE in the laminae were 8.93, 6.82, and 8.63 GPa for A. mangium , M. eminii , and M. azedarach , respectively. When the laminae from a species were randomly laminated, the simulated MOE values of glulam were 8.94, 6.82, and 8.66 GPa for A. mangium, M. eminii , and M. azedarach, respectively. When laminae with a high, medium, and low MOE were laminated at outer, middle, and inner layers of glulam, respectively, the simulated MOE values of glulam increased by about 5 % to 15 % compared to the values of a randomly laminated one. It is concluded that glulam with a high MOE can be produced from fast-growing tree species grown in community forests in Indonesia.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Socio economical evaluation of Uncaria gambir cultivation systems in West Sumatra, Indonesia","authors":"David Malik, Aflizar, Synthia Ona Guserike Afner, Akira Fukuda, T. Masunaga","doi":"10.3759/tropics.ms19-15","DOIUrl":"https://doi.org/10.3759/tropics.ms19-15","url":null,"abstract":"Uncaria gambir (Ug) is the main ingredient for producing Gambir which is an international trading commodity that Indonesia has shared its production of 80 % in the world. This paper investigates the type of Ug cultivation system in West Sumatra and its contribution to farmers’ income security. Rapid rural appraisal was used for collecting data. Economic analysis is carried out consisting of Benefit and Cost ratio (B/C Ratio), net present value (NPV), internal rate of return (IRR), sensitivity test on the discount rate and Gambir production. Six Ug cultivation systems were found, namely Ug-Mono, Ug-Rubber, and Ug-Areca nut in Lima Puluh Kota regency (LPKR) and in Pesisir Selatan regency (PSR) Ug-Durian, Ug-Durian-Jengkol and Ug-Durian-Petai. In general, The Ug cultivation systems combined with Durian and Jengkol or Petai, that were found valuable additional crops, were more stable in income generation against to the fluctuation of Ug production and Gambir price. Among the six, the highest B/C Ratio was found in Ug-Durian-Jengkol (2.8) while the lowest was in Ug-Mono and Ug-Rubber (1.9). Moreover, Ug-Durian-Jengkol show better NPV and IRR in the most conditions of Gambir price from 10,000 to100,000 Rp kg as well as Gambir production from 2,400 to 4,800 kg y. On the other hand, NPV and IRR of Ug-Mono, -Rubber or -Areca nut systems sharply decreased with the decrease of Gambir price. These systems relied more on Ug production and Gambir price in the income generation. It exhibited the vulnerability of income structure of these systems. From the results, to secure farmers’ income from volatility of Ug production and Gambir price, this research suggested Ug cultivation systems combining with durian or other profitable cash crops in West Sumatra.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial variations in the decay coefficients of forest ecosystems in East and Southeast Asia","authors":"T. Yoneda, H. Mizunaga, T. Okuda, S. Fujii, S. Nishimura, Shuhei Nishi, Hidenori Aimura, Taisei Hamanaka, W. R. Kadir, Erizal Mukhtar","doi":"10.3759/tropics.ms19-02","DOIUrl":"https://doi.org/10.3759/tropics.ms19-02","url":null,"abstract":"We assessed spatial variation in the decay coefficients of fine wood litter on the forest floor in four forest formations in East and Southeast Asia. We used a novel approach to incorporate fragmentation loss in the decomposition process within four plots, each several hectares in area. The spatial patterns showed significant correlations with some biotic, edaphic, topographic, and climatic factors. Variation in the lowland tropical rainforest was driven largely by the feeding behaviors of termites. Variation in the hill dipterocarp forest exhibited no clear correlations with topographic parameters due to complementarity of decay activities by fungi and termites through segregation of their habitat between concave and convex sites, respectively. The subtropical rainforest showed variations associated with habitats distinguished by understory communities, reflecting edaphic conditions. Variation in the warm-temperate lucidophyll forest showed a clear negative correlation with slope convexity. The maximum area of spatial autocorrelation for the decay coefficient was used as the unit area for identification of significant relationships between decay coefficients and net primary productivity for aboveground coarse woody organs in terms of spatial variations, except in the subtropical forest plot. The ecological features of the four research plots were assessed based on spatial variation in structural and functional parameters over the unit areas or among the understory communities. Our results imply that 1) the positive correlations between decay coefficients and net primary productivity in two plots in a tropical zone were realized by spatial properties of the death rates of trees being higher or even at sites with higher decay coefficients and 2) the negative correlations in two plots in subtropical and warm-temperate zones were maintained by increasing the death rates on convex sites through frequent disturbance by typhoons. Inter- and intrasite variations in decay coefficients were evaluated using a probability density function of two-dimensional standard normal distributions regressed from data collected in the study area.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42866180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of thinning on anatomical characteristics and wood properties of 12-year-old Eucalyptus camaldulensis trees planted in Thailand","authors":"Haruna Aiso-Sanada, F. Ishiguri, S. Diloksumpun, I. Nezu, J. Tanabe, J. Ohshima, S. Yokota","doi":"10.3759/tropics.ms19-04","DOIUrl":"https://doi.org/10.3759/tropics.ms19-04","url":null,"abstract":"To clarify the effects of thinning on the growth and wood quality of Eucalyptus camaldulensis trees grown in Thailand, the growth characteristics, anatomical characteristics, and wood properties of T5 clones, which are used on plantations to produce pulpwood, were investigated. Core samples were collected from trees grown on both thinned and unthinned (i.e., control) plots. The effects of thinning on the trees’ anatomical characteristics and wood properties were evaluated at bark side (2 cm from the bark) of the tree. We identified significant differences between the two plots in terms of stem diameter, wood volume, wall thickness of wood fiber, moisture content, and basic density. However, trends in the radial variation of the measured characteristics were almost the same between the thinned and control plots. These results suggest that prolonged rotation age and subsequent thinning do not negatively affect the quality of solid wood produced by E. camaldulensis.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/tropics.ms19-04","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43049038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immigration and adaptation of the Iban from rural to urban outskirts in Sarawak, Malaysia","authors":"M. Ichikawa","doi":"10.3759/tropics.ms18-14","DOIUrl":"https://doi.org/10.3759/tropics.ms18-14","url":null,"abstract":"This paper aims at clarifying how immigrants from rural areas use the outskirts of Bintulu City in Sarawak, Malaysia and form places of residence there. The area under tropical rain forest climate conditions in Southeast Asia generally has a sparse population. In recent decades, urban areas have started to grow rapidly. In the state of Sarawak, urban areas have developed, and the formation of squatter areas by immigrants from rural areas has been reported. Until a few decades ago, after leaving urban areas, the landscape immediately changed from an urban landscape into a rural one consisting mainly of forests, dotted with swidden farms and longhouses. Recently, however, in areas such as those after leaving the urban area (urban outskirts) of Bintulu City, in addition to shops and offices managed by the Chinese, longhouse communities (LHCs) formed by immigrants from rural areas are densely dotted. In such LHCs, dwellings and ways of living are observed to have different characteristics from those in rural LHCs and squatter areas in urban areas. Characteristics of LHCs in urban outskirts are shown below. Regarding land acquisition, the land was in most cases purchased from former occupants. Regarding members of the LHCs, in LHCs formed before the 1960s, many males married in and households moved in around the 1970s and 1980s. On the other hand, in newly formed LHCs, in many cases no kinship links or very weak kinship links between households are observed. Regarding livelihoods, many members of LHCs work in the urban area, while some who own land cultivate cash crops such as oil palm. Suburban formation has begun as a mix of such LHCs, Chinese shops and offices, and forests in the study area.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/tropics.ms18-14","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43951478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deforestation and forest fragmentation in and around Endau-Rompin National Park, Peninsular Malaysia","authors":"Y. S. Foo, S. Numata","doi":"10.3759/tropics.ms18-16","DOIUrl":"https://doi.org/10.3759/tropics.ms18-16","url":null,"abstract":"Protected areas (PAs) are crucial for conserving biodiversity, but there is controversy over whether they effectively reduce deforestation because, for many of the PAs evaluated to date, pressure from deforestation occurred both inside the PAs and in the areas surroundings them. This is especially the case for tropical PAs in Southeast Asia. We examined the impact of a protected area on tropical rainforests inside and surrounding Endau-Rompin National Park (ERNP) in southern Peninsular Malaysia by mapping and analyzing forest cover changes and fragmentation between 1992 and 2016. The results showed that the forests inside ERNP were well protected, but greater forest loss and fragmentation were found surrounding ERNP, especially beyond the 10-km buffer zone of the park, due to large-scale agricultural land conversion, particularly for oil palm plantation. The deforestation rate in areas surrounding PAs in the region increased from 250 ha yr − 1 during 1992 - 2007 to 1,700 ha yr − 1 during 2012 - 2016. In the buffer zone (BZ), the deforestation rate was extremely high during 2007 - 2012 at 1,800 ha yr − 1 , but decreased to 440 ha yr − 1 during 2012 - 2016. This suggests that in this region, PAs might be ineffective against deforestation in their surrounding areas. Continual deforestation and fragmentation are expected to occur surrounding ERNP, threatening its protected boundary. These activities may reduce the effectiveness of ERNP for wildlife habitat conservation.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/tropics.ms18-16","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43411176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}