Ryota Kitamura, Naoki Okada, M. Sakai, T. Visaratana, Ratana Thai-ngam, B. Hongthong, Kriangkrai Potingam
We examined the ‘catalyzing effect’, by which the establishment of indigenous species and secondary succession are facilitated in plantations. A tree census was conducted at two 24-year-old plantations (agroforestry and eucalyptus plots), and a grassland in northeast Thailand. Three natural forests adjacent to the two plantation plots and the grassland plot were also investigated to evaluate their possible influence on the catalyzing effect based on the differences in species diversity and the intensity of disturbance among the natural forests. The catalyzing effect seemed to be observed at the study site; the two plantations had more individuals and species of indigenous trees than the grassland, indicating faster natural regeneration of the formers than the latter. Although our results found the tendency of the catalyzing effect, further studies using sufficient plot replication are required to verify the generality of the effect.
{"title":"Regeneration of natural-forest species in plantations of fast-growing species in northeast Thailand","authors":"Ryota Kitamura, Naoki Okada, M. Sakai, T. Visaratana, Ratana Thai-ngam, B. Hongthong, Kriangkrai Potingam","doi":"10.3759/TROPICS.MS17-04","DOIUrl":"https://doi.org/10.3759/TROPICS.MS17-04","url":null,"abstract":"We examined the ‘catalyzing effect’, by which the establishment of indigenous species and secondary succession are facilitated in plantations. A tree census was conducted at two 24-year-old plantations (agroforestry and eucalyptus plots), and a grassland in northeast Thailand. Three natural forests adjacent to the two plantation plots and the grassland plot were also investigated to evaluate their possible influence on the catalyzing effect based on the differences in species diversity and the intensity of disturbance among the natural forests. The catalyzing effect seemed to be observed at the study site; the two plantations had more individuals and species of indigenous trees than the grassland, indicating faster natural regeneration of the formers than the latter. Although our results found the tendency of the catalyzing effect, further studies using sufficient plot replication are required to verify the generality of the effect.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"26 1","pages":"111-121"},"PeriodicalIF":0.7,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS17-04","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70009892","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}
Asano Iku, T. Itioka, A. Kawakita, H. Goto, A. Ueda, Usun Shimizu-Kaya, P. Meleng
A bark beetle Coccotrypes gedeanus Eggers (Coleoptera: Curculionidae: Scolytinae) is a dominant insect seed predator of dipterocarp fruits in the lowland tropical rainforests of Southeast Asia. In this study, the host preference and host range of C. gedeanus was determined by sampling 22,216 fruits from 137 species of 59 genera belonging to 24 families in a primary lowland mixed dipterocarp forest in Borneo. Coccotrypes gedeanus adults were found in the fruits of 51 species from 19 genera belonging to 13 families, and were observed to settle in the fruits of 34 species of 11 genera belonging to 6 families to initiate breeding. Except one plant species, the rest of the 34 plant species were confirmed to bear “nut” or “drupe” type fruit. These results suggested that a population of C. gedeanus utilize seeds of various plant species simultaneously. The polyphagy of the bark beetle might be adaptive for survival in the Bornean tropical rain forests where the density of each plant species is low, and most plants produce fruits at unpredictably long intervals. Our results also suggested that the characteristics of fruit might affect the host plant preference of C. gedeanus adults and/or the growth performance of C. gedeanus larvae.
{"title":"High degree of polyphagy in a seed-eating bark beetle, Coccotrypes gedeanus (Coleoptera: Curculionidae: Scolytinae), during a community-wide fruiting event in a Bornean tropical rainforest","authors":"Asano Iku, T. Itioka, A. Kawakita, H. Goto, A. Ueda, Usun Shimizu-Kaya, P. Meleng","doi":"10.3759/TROPICS.MS18-07","DOIUrl":"https://doi.org/10.3759/TROPICS.MS18-07","url":null,"abstract":"A bark beetle Coccotrypes gedeanus Eggers (Coleoptera: Curculionidae: Scolytinae) is a dominant insect seed predator of dipterocarp fruits in the lowland tropical rainforests of Southeast Asia. In this study, the host preference and host range of C. gedeanus was determined by sampling 22,216 fruits from 137 species of 59 genera belonging to 24 families in a primary lowland mixed dipterocarp forest in Borneo. Coccotrypes gedeanus adults were found in the fruits of 51 species from 19 genera belonging to 13 families, and were observed to settle in the fruits of 34 species of 11 genera belonging to 6 families to initiate breeding. Except one plant species, the rest of the 34 plant species were confirmed to bear “nut” or “drupe” type fruit. These results suggested that a population of C. gedeanus utilize seeds of various plant species simultaneously. The polyphagy of the bark beetle might be adaptive for survival in the Bornean tropical rain forests where the density of each plant species is low, and most plants produce fruits at unpredictably long intervals. Our results also suggested that the characteristics of fruit might affect the host plant preference of C. gedeanus adults and/or the growth performance of C. gedeanus larvae.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"27 1","pages":"59-66"},"PeriodicalIF":0.7,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS18-07","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010649","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}
We observed species composition, diversity, and stand structure in the tropical lower montane forests of a hilly region in eastern Myanmar and examined the impacts of anthropogenic disturbances on the forest stands. From our survey of 58 sample plots (30 m × 30 m), we categorized four stand types using nonmetric multi-dimensional scaling (NMS) ordination. The four stand types exhibited significant contributions of various anthropogenic impacts, reflecting differences in local livelihoods within different varying landscapes. Anthropogenic disturbances, especially the extraction of firewood, can significantly affect the stand structure of forests and, in turn, the species composition and tree diversity. Some early successional species such as Phyllanthus albizzioides and Albizia odoratissima became indicator species of highly disturbed forests. As firewood is mainly extracted from privately owned forests rather than communal forests, land tenure was also an important factor governing the intensity of anthropogenic disturbances. Species richness and diversity values decreased in stand types exposed to more severe anthropogenic disturbances. Stem density was significantly higher in highly disturbed forests. This was a result of higher numbers of multi-stemmed individuals, which revealed the effect of cutting larger stems for firewood extraction. In old secondary forests, the lack of young trees under the canopy may threaten future forest regeneration. Depending on varying forest conditions and the local population ʼ s input, different forest management activities should be applied to forests to optimize production and protection for the local community.
研究了缅甸东部丘陵地区热带低山林的物种组成、多样性和林分结构，并探讨了人为干扰对林分结构的影响。通过对58个样地(30 m × 30 m)的调查，采用非度量多维尺度(NMS)排序将林分类型划分为4种。四种林分类型均表现出不同人为影响的显著贡献，反映了不同景观下当地生计的差异。人为干扰，特别是采伐柴火，会显著影响林分结构，进而影响物种组成和树木多样性。一些早期演替的物种，如白菖蒲和臭菖蒲，成为高度干扰林的指示种。由于木柴主要从私人拥有的森林而不是公共森林中提取，土地所有权也是控制人为干扰强度的一个重要因素。人为干扰越严重，林分类型的物种丰富度和多样性值越低。高度扰动林的茎密度显著高于扰动林。这是多茎个体数量增加的结果，这揭示了砍伐较大茎以提取柴火的影响。在古老的次生林中，树冠下幼树的缺乏可能会威胁到未来的森林再生。根据不同的森林条件和当地人口的投入，应对森林实施不同的森林管理活动，以优化当地社区的生产和保护。
{"title":"Species composition, diversity, and stand structure of tropical lower montane forests resulting from various human impacts on the Shan Plateau, eastern Myanmar","authors":"Phyu Phyu Lwin, M. Kanzaki","doi":"10.3759/TROPICS.MS17-03","DOIUrl":"https://doi.org/10.3759/TROPICS.MS17-03","url":null,"abstract":"We observed species composition, diversity, and stand structure in the tropical lower montane forests of a hilly region in eastern Myanmar and examined the impacts of anthropogenic disturbances on the forest stands. From our survey of 58 sample plots (30 m × 30 m), we categorized four stand types using nonmetric multi-dimensional scaling (NMS) ordination. The four stand types exhibited significant contributions of various anthropogenic impacts, reflecting differences in local livelihoods within different varying landscapes. Anthropogenic disturbances, especially the extraction of firewood, can significantly affect the stand structure of forests and, in turn, the species composition and tree diversity. Some early successional species such as Phyllanthus albizzioides and Albizia odoratissima became indicator species of highly disturbed forests. As firewood is mainly extracted from privately owned forests rather than communal forests, land tenure was also an important factor governing the intensity of anthropogenic disturbances. Species richness and diversity values decreased in stand types exposed to more severe anthropogenic disturbances. Stem density was significantly higher in highly disturbed forests. This was a result of higher numbers of multi-stemmed individuals, which revealed the effect of cutting larger stems for firewood extraction. In old secondary forests, the lack of young trees under the canopy may threaten future forest regeneration. Depending on varying forest conditions and the local population ʼ s input, different forest management activities should be applied to forests to optimize production and protection for the local community.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"26 1","pages":"71-82"},"PeriodicalIF":0.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS17-03","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48609997","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}
Although it is said that societies in Southeast Asian countries are loosely structured, every area has its own attributes. In such vastly differing societies, the mode of organizing themselves differs between ethnic groups, as well as geographic location. The objective of this study is to understand how local people respond to exogenous development by focusing on their mode of organizing themselves, through dyadic relationships or individual ties between peoples, groups, and development organizations. One of the Dayak ethnic groups, which can be found in the central region of Borneo, the Bahau, make swiddens along rivers. They call a complex of these swiddens “daleh”. The Bahau people organize a reciprocal labor exchange known as pelaʼdo with the people who have swiddens in the same daleh, but recently their method of organizing pelaʼdo has undergone changes. The people have adapted themselves to the introduction of tight development organizations (farming groups), in such a way as to allow for coexistence with customary loose organizations (pelaʼdo).
{"title":"How do swiddeners organize small groups and react to exogenous development? A case study of the Bahau in East Kalimantan, Indonesia","authors":"Naoko Takata, M. Inoue","doi":"10.3759/TROPICS.MS16-19","DOIUrl":"https://doi.org/10.3759/TROPICS.MS16-19","url":null,"abstract":"Although it is said that societies in Southeast Asian countries are loosely structured, every area has its own attributes. In such vastly differing societies, the mode of organizing themselves differs between ethnic groups, as well as geographic location. The objective of this study is to understand how local people respond to exogenous development by focusing on their mode of organizing themselves, through dyadic relationships or individual ties between peoples, groups, and development organizations. One of the Dayak ethnic groups, which can be found in the central region of Borneo, the Bahau, make swiddens along rivers. They call a complex of these swiddens “daleh”. The Bahau people organize a reciprocal labor exchange known as pelaʼdo with the people who have swiddens in the same daleh, but recently their method of organizing pelaʼdo has undergone changes. The people have adapted themselves to the introduction of tight development organizations (farming groups), in such a way as to allow for coexistence with customary loose organizations (pelaʼdo).","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"26 1","pages":"83-97"},"PeriodicalIF":0.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS16-19","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49546931","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}
It is well recognized that the marine resources of the Philippines are increasingly and severely damaged by climate change and human interventions, including overfishing and destructive fishing. To manage its marine resources, the government has implemented marine protected area (MPA) systems, expecting the involvement of local communities in its management. Although over 1,600 MPAs had been established by 2014, it is reported that they are not effectively managed. The purpose of the study is to determine the current conditions of MPAs in the Philippines using the MPA Management Effectiveness Assessment Tool (MEAT) developed in 2010, and to identify how MEAT reflects reality through interviews at two MPAs. The MEAT data analysis shows that MEAT has not yet been fully utilized and its information is not representative of all the MPAs in the country. So far, as based on the information provided by MEAT, less than half of the MPAs are effectively managed and management effectiveness is not related to the age of the MPA or evenly distributed across regions. The field study, although limited by the fact that it is based on only two MPAs, raises the question as to whether or not local evaluation has been conducted as intended. Unlike the high expectations of communities as effective MPA management entities, local people in the two cases rely more on local government. The results suggest the necessity of further studies on monitoring the MEAT evaluation process and the importance of field studies regarding the effectiveness of community-based MPA management.
{"title":"Conditions of marine protected areas (MPAs) in the Philippines observed through the MEAT database and a reality of evaluation system and the community based management in two MPA cases","authors":"Yuta Ito, M. Toda, M. Masuda","doi":"10.3759/TROPICS.MS16-04","DOIUrl":"https://doi.org/10.3759/TROPICS.MS16-04","url":null,"abstract":"It is well recognized that the marine resources of the Philippines are increasingly and severely damaged by climate change and human interventions, including overfishing and destructive fishing. To manage its marine resources, the government has implemented marine protected area (MPA) systems, expecting the involvement of local communities in its management. Although over 1,600 MPAs had been established by 2014, it is reported that they are not effectively managed. The purpose of the study is to determine the current conditions of MPAs in the Philippines using the MPA Management Effectiveness Assessment Tool (MEAT) developed in 2010, and to identify how MEAT reflects reality through interviews at two MPAs. The MEAT data analysis shows that MEAT has not yet been fully utilized and its information is not representative of all the MPAs in the country. So far, as based on the information provided by MEAT, less than half of the MPAs are effectively managed and management effectiveness is not related to the age of the MPA or evenly distributed across regions. The field study, although limited by the fact that it is based on only two MPAs, raises the question as to whether or not local evaluation has been conducted as intended. Unlike the high expectations of communities as effective MPA management entities, local people in the two cases rely more on local government. The results suggest the necessity of further studies on monitoring the MEAT evaluation process and the importance of field studies regarding the effectiveness of community-based MPA management.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"26 1","pages":"27-36"},"PeriodicalIF":0.7,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS16-04","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44872503","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}
Ryosuke Nakamura, T. Oyabu, J. Ndufa, B. K. Kigwa, K. Yoshikawa
Midday transpiration rates and daily pan evaporation from forest floor and open area were measured to determine an effective way of controlling water loss from a Melia volkensii plantation. The research was conducted at an M. volkensii plantation in Tiva Pilot Forest, Kenya, during April and May 2014. A leaf porometer (LI-1600) was used to measure midday transpiration rates per unit leaf area (Ta) from 11:00 h to 13:00 h for four trees at three different leaf heights: top (A), middle (B), and bottom (C) layers of a crown. Midday transpiration rate per layer (Tl) and midday transpiration rate per tree (Tt) were estimated based on Ta and leaf area (LA) of layers. Daily pan evaporation from forest floor and open area were measured using 25 and two evaporation pans, respectively. Ta values for layer A were not significantly different among sample trees, while Tl values for layer A were significantly different, indicating the influence of LA on water loss through transpiration. Since Tl from layers B and C accounted for half of Tt, pruning of these layers could cause a 50 % reduction in water loss through transpiration. Daily pan evaporation in the plantation was approximately 70 % lower than that in the open area. Therefore, the layer A left after pruning should keep water loss through evaporation from the forest floor lower than that from the open area. Further research is required to determine the effect of pruning on reduction of water loss from the plantation.
{"title":"Midday transpiration rates and daily pan evaporation from a Melia volkensii plantation during the rainy season in a semi-arid area in Kenya","authors":"Ryosuke Nakamura, T. Oyabu, J. Ndufa, B. K. Kigwa, K. Yoshikawa","doi":"10.3759/TROPICS.MS16-07","DOIUrl":"https://doi.org/10.3759/TROPICS.MS16-07","url":null,"abstract":"Midday transpiration rates and daily pan evaporation from forest floor and open area were measured to determine an effective way of controlling water loss from a Melia volkensii plantation. The research was conducted at an M. volkensii plantation in Tiva Pilot Forest, Kenya, during April and May 2014. A leaf porometer (LI-1600) was used to measure midday transpiration rates per unit leaf area (Ta) from 11:00 h to 13:00 h for four trees at three different leaf heights: top (A), middle (B), and bottom (C) layers of a crown. Midday transpiration rate per layer (Tl) and midday transpiration rate per tree (Tt) were estimated based on Ta and leaf area (LA) of layers. Daily pan evaporation from forest floor and open area were measured using 25 and two evaporation pans, respectively. Ta values for layer A were not significantly different among sample trees, while Tl values for layer A were significantly different, indicating the influence of LA on water loss through transpiration. Since Tl from layers B and C accounted for half of Tt, pruning of these layers could cause a 50 % reduction in water loss through transpiration. Daily pan evaporation in the plantation was approximately 70 % lower than that in the open area. Therefore, the layer A left after pruning should keep water loss through evaporation from the forest floor lower than that from the open area. Further research is required to determine the effect of pruning on reduction of water loss from the plantation.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"26 1","pages":"17-25"},"PeriodicalIF":0.7,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS16-07","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43263916","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}
Agarwood is one of the most valuable non-timber forest products harvested from the heart of the mountains of Southeast Asian tropical rain forests. Some species of trees in the genus Aquilaria (Thymelaeaceae) accumulate resins in parts of their trunks. Agarwood has a long history as a trade good, although ecological data and economic assessments regarding agarwood harvesting in natural habitats are lacking. The author performed field surveys in the upper reaches of the Baram River in Sarawak, Malaysia, to assess the possibility of harvesting natural agarwood sustainably. In 2004, the habitat density of Aquilaria beccariana around village L was less than one tree per ha, and only relatively mature trees produced resins in their trunks. The introduction of commercial logging and hill rice cultivation damages the habitat of A. beccariana . Thus, the conservation of primary forests is essential for natural agarwood harvesting. The local Penan people only harvest the portions of the trees where resins accumulate, which allows the trees to survive. However, exploitative agarwood harvesting has begun in this area since the early 2010s, as a result of intrusions by outsiders. Thus, one cannot assume that all agarwood harvesting in Sarawak is being conducted sustainably. Meanwhile, in areas with no traces of outside intruders, the number of mature agarwood-producing trees has been maintained, suggesting that the method of agarwood harvesting used by the villagers is sustainable. To ensure that agarwood harvesting is sustainable, traceability that is based on more strictly defined and more detailed information regarding all of the steps in the agarwood supply chain is required.
{"title":"Sustainable Harvesting and Conservation of Agarwood: A Case Study from the Upper Baram River in Sarawak, Malaysia","authors":"K. Kanazawa","doi":"10.3759/TROPICS.MS15-16","DOIUrl":"https://doi.org/10.3759/TROPICS.MS15-16","url":null,"abstract":"Agarwood is one of the most valuable non-timber forest products harvested from the heart of the mountains of Southeast Asian tropical rain forests. Some species of trees in the genus Aquilaria (Thymelaeaceae) accumulate resins in parts of their trunks. Agarwood has a long history as a trade good, although ecological data and economic assessments regarding agarwood harvesting in natural habitats are lacking. The author performed field surveys in the upper reaches of the Baram River in Sarawak, Malaysia, to assess the possibility of harvesting natural agarwood sustainably. In 2004, the habitat density of Aquilaria beccariana around village L was less than one tree per ha, and only relatively mature trees produced resins in their trunks. The introduction of commercial logging and hill rice cultivation damages the habitat of A. beccariana . Thus, the conservation of primary forests is essential for natural agarwood harvesting. The local Penan people only harvest the portions of the trees where resins accumulate, which allows the trees to survive. However, exploitative agarwood harvesting has begun in this area since the early 2010s, as a result of intrusions by outsiders. Thus, one cannot assume that all agarwood harvesting in Sarawak is being conducted sustainably. Meanwhile, in areas with no traces of outside intruders, the number of mature agarwood-producing trees has been maintained, suggesting that the method of agarwood harvesting used by the villagers is sustainable. To ensure that agarwood harvesting is sustainable, traceability that is based on more strictly defined and more detailed information regarding all of the steps in the agarwood supply chain is required.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"25 1","pages":"139-146"},"PeriodicalIF":0.7,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS15-16","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46643750","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}
Y. Kiyono, Eriko Ito, Yukako Monda, Jumpei Toriyama, H. Saito, Naoyuki Furuya, Thy Sum, Bora Tith, Nang Keth, Samkol Keth, Ly Chandararity, Op Phallaphearaoth, Sophal Chann, H. Sokh
To study the feasibility of determining the mean annual aboveground biomass gain of tropical seasonal forests at the national scale, we estimated the gain (i.e., increase due to growth of living trees) and loss (i.e., decrease due to tree death) of aboveground tree stand biomass (stand AGB) using 49 permanent sample plots distributed nationwide for 139 observation periods from 2005 to 2015 in Cambodia. In a linear mixed-effects model, stand AGB gain was predicted to increase with the initial stand AGB: Stand AGB gain=0.0165 Stand AGB+2.20 (n=139, P<0.0001, R=0.4531, RMSE=2.84), where Stand AGB gain is the sum of tree AGB growth (Mg ha year), and Stand AGB is the sum of initial tree AGBs (Mg ha). The mean estimated stand AGB gain was 4.79 Mg ha year for an average initial stand AGB of 155.5 Mg ha. The annual stand AGB loss was<20 % of the initial stand AGB and the influence of stand AGB loss on stand AGB gain was negligible. The 2006 IPCC Guidelines for National Greenhouse Gas Inventories assigned stand-age-dependent values of default annual stand AGB gain for tropical natural forests. However, age is difficult to determine in tropical trees. Our stand-age-independent approach based on the stand AGB offers a practical method for assessing the AGB gain of tropical natural forests.
{"title":"A feasibility study for determining the mean annual aboveground biomass gain of tropical seasonal forests in Cambodia","authors":"Y. Kiyono, Eriko Ito, Yukako Monda, Jumpei Toriyama, H. Saito, Naoyuki Furuya, Thy Sum, Bora Tith, Nang Keth, Samkol Keth, Ly Chandararity, Op Phallaphearaoth, Sophal Chann, H. Sokh","doi":"10.3759/TROPICS.MS15-27","DOIUrl":"https://doi.org/10.3759/TROPICS.MS15-27","url":null,"abstract":"To study the feasibility of determining the mean annual aboveground biomass gain of tropical seasonal forests at the national scale, we estimated the gain (i.e., increase due to growth of living trees) and loss (i.e., decrease due to tree death) of aboveground tree stand biomass (stand AGB) using 49 permanent sample plots distributed nationwide for 139 observation periods from 2005 to 2015 in Cambodia. In a linear mixed-effects model, stand AGB gain was predicted to increase with the initial stand AGB: Stand AGB gain=0.0165 Stand AGB+2.20 (n=139, P<0.0001, R=0.4531, RMSE=2.84), where Stand AGB gain is the sum of tree AGB growth (Mg ha year), and Stand AGB is the sum of initial tree AGBs (Mg ha). The mean estimated stand AGB gain was 4.79 Mg ha year for an average initial stand AGB of 155.5 Mg ha. The annual stand AGB loss was<20 % of the initial stand AGB and the influence of stand AGB loss on stand AGB gain was negligible. The 2006 IPCC Guidelines for National Greenhouse Gas Inventories assigned stand-age-dependent values of default annual stand AGB gain for tropical natural forests. However, age is difficult to determine in tropical trees. Our stand-age-independent approach based on the stand AGB offers a practical method for assessing the AGB gain of tropical natural forests.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"25 1","pages":"127-138"},"PeriodicalIF":0.7,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS15-27","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46920037","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}
We assessed the spatial variations in net ecosystem productivity (NEP) using a biometric method based on the dynamics of coarse woody organs in a primeval lowland tropical rain forest in Pasoh, Peninsular Malaysia. The average NEP and carbon stocks in biomass and coarse woody debris over 15 years from 1990 to 2005 were -0.75 t C ha y, 205 t C ha, and 22 t C ha, respectively. However, there were large spatial variations among the five communities, which were correlated with edaphic and topographical features. A mature carbon cycling system with high biomass (where NEP ≈ 0) was observed in a subcommunity on west-facing slopes of the hill community. Over the course of 15 years, a drought and storms were the major agents causing forest disturbances. These factors affected the spatial variations of NEP through not only spatial distribution patterns in species with different sensitivities to stress but also differences in the extent of stress depending on topography. We modeled the disturbance regime as elapsing from 1907 to 1947 basing on observed values of net primary production and biomass of five communities during the 15 years. When we extrapolated high mortalities of trees under this regime, our simulation suggested that a 50-ha plot will remain a carbon-source system for the atmosphere at an average rate of NEP=-0.95 t C ha y until 2060, with different biomass decreases among these five communities.
本文采用基于粗木本器官动态的生物识别方法对马来西亚半岛帕索原始低地热带雨林净生态系统生产力(NEP)的空间变化进行了评估。1990 ~ 2005年15 a间生物量和粗木屑的平均NEP和碳储量分别为-0.75 t C /年、205 t C /年和22 t C /年。但是，5个群落间存在较大的空间差异，这与土壤地形特征有关。在西坡山地群落的亚群落中发现了一个成熟的高生物量(NEP≈0)的碳循环系统。在15年的时间里，干旱和风暴是造成森林紊乱的主要因素。这些因素不仅通过不同胁迫敏感性物种的空间分布格局，而且通过不同地形胁迫程度的差异影响NEP的空间变化。我们基于15年间5个群落的净初级生产量和生物量的观测值，模拟了1907 - 1947年的扰动状态。当我们推断在这种情况下树木的高死亡率时，我们的模拟表明，直到2060年，50公顷的地块将以平均NEP=-0.95 t C / h的速率保持大气的碳源系统，这五个群落的生物量减少不同。
{"title":"Spatial variations in the net ecosystem productivity of a primeval tropical forest in a 50-ha plot in Pasoh, Peninsular Malaysia","authors":"T. Yoneda, H. Mizunaga, T. Okuda, W. R. Kadir","doi":"10.3759/TROPICS.MS16-12","DOIUrl":"https://doi.org/10.3759/TROPICS.MS16-12","url":null,"abstract":"We assessed the spatial variations in net ecosystem productivity (NEP) using a biometric method based on the dynamics of coarse woody organs in a primeval lowland tropical rain forest in Pasoh, Peninsular Malaysia. The average NEP and carbon stocks in biomass and coarse woody debris over 15 years from 1990 to 2005 were -0.75 t C ha y, 205 t C ha, and 22 t C ha, respectively. However, there were large spatial variations among the five communities, which were correlated with edaphic and topographical features. A mature carbon cycling system with high biomass (where NEP ≈ 0) was observed in a subcommunity on west-facing slopes of the hill community. Over the course of 15 years, a drought and storms were the major agents causing forest disturbances. These factors affected the spatial variations of NEP through not only spatial distribution patterns in species with different sensitivities to stress but also differences in the extent of stress depending on topography. We modeled the disturbance regime as elapsing from 1907 to 1947 basing on observed values of net primary production and biomass of five communities during the 15 years. When we extrapolated high mortalities of trees under this regime, our simulation suggested that a 50-ha plot will remain a carbon-source system for the atmosphere at an average rate of NEP=-0.95 t C ha y until 2060, with different biomass decreases among these five communities.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"57 1","pages":"1-15"},"PeriodicalIF":0.7,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS16-12","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010168","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}
Suthathip Umnouysin, T. Sangtiean, Tamotsu Sato, S. Poungparn
Coarse woody debris (CWD) is an important component in forest ecosystems. A knowledge of CWD respiration, in addition to its storage, is necessary to clarify the carbon dynamics in a forest ecosystem. However, data on CWD respiration in mangrove forests is still scarce. We measured the carbon dioxide (CO2) efflux rates from the CWD respiration of three mangrove species (Avicennia alba, Rhizophora spp. and Xylocarpus granatum) using gas chromatography (GC) and sodalime (SL) methods. The results revealed that the CO2 efflux rates obtained by the SL method were not significantly different to those obtained by the GC method for all three species. Therefore, the CO2 efflux rate from CWD respiration of the three mangrove species was measured by the SL method without calibration. The CO2 efflux rate of A. alba CWD was significantly higher than the other two species, whereas the CO2 efflux rates of Rhizophora spp. and X. granatum were not different. The differences in the CO2 efflux among the species was likely to be due to their different wood densities and water contents, and the interaction of these terms. Although, the CO2 efflux rate from CWD respiration showed a relatively low value in a comparison to that from soil respiration, the CO2 efflux rates from CWD respiration should still be measured for clarifying the carbon dynamics in a mangrove ecosystem, especially those with a high CWD mass.
{"title":"Comparative carbon dioxide efflux rates from respiration of coarse woody debris among three mangrove species in Thailand","authors":"Suthathip Umnouysin, T. Sangtiean, Tamotsu Sato, S. Poungparn","doi":"10.3759/TROPICS.MS16-16","DOIUrl":"https://doi.org/10.3759/TROPICS.MS16-16","url":null,"abstract":"Coarse woody debris (CWD) is an important component in forest ecosystems. A knowledge of CWD respiration, in addition to its storage, is necessary to clarify the carbon dynamics in a forest ecosystem. However, data on CWD respiration in mangrove forests is still scarce. We measured the carbon dioxide (CO2) efflux rates from the CWD respiration of three mangrove species (Avicennia alba, Rhizophora spp. and Xylocarpus granatum) using gas chromatography (GC) and sodalime (SL) methods. The results revealed that the CO2 efflux rates obtained by the SL method were not significantly different to those obtained by the GC method for all three species. Therefore, the CO2 efflux rate from CWD respiration of the three mangrove species was measured by the SL method without calibration. The CO2 efflux rate of A. alba CWD was significantly higher than the other two species, whereas the CO2 efflux rates of Rhizophora spp. and X. granatum were not different. The differences in the CO2 efflux among the species was likely to be due to their different wood densities and water contents, and the interaction of these terms. Although, the CO2 efflux rate from CWD respiration showed a relatively low value in a comparison to that from soil respiration, the CO2 efflux rates from CWD respiration should still be measured for clarifying the carbon dynamics in a mangrove ecosystem, especially those with a high CWD mass.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":"26 1","pages":"49-57"},"PeriodicalIF":0.7,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS16-16","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70009819","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}
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