T. Ichie, Aogu Yoneyama, T. Hashimoto, Ayumi Tanaka‐Oda, K. Kusin, T. Kenzo
Large areas of the tropical peat swamp forests in Central Kalimantan were drained to be converted into rice fields and then abandoned. A change in the soil water level due to drainage in the forests must have had a big impact on the ecology and ecophysiology of the trees in the drained remnant forests. The leaf traits of these trees in particular may have been directly or indirectly affected by drainage because of their high sensitivity to environmental change. To understand the influence of drainage on leaf traits, we investigated leaf morphological and physiological differences between intact and drained peat swamp forests in Palangka Raya, Indonesia, using 14 species distributed over both types of forests. We compared the leaf mass per unit area (LMA), leaf toughness, leaf area- and mass-based nitrogen content (N area and N mass ), carbon/nitrogen ratio, total phenolics, condensed tannin and lignin content and carbon isotope ratio ( δ 13 C) of both types of forest trees. In the drained forest, trees had higher values in LMA, N area , and δ 13 C than in the intact forest, suggesting that such trees adjust themselves to dry conditions to increase photosynthetic ability with high water use efficiency compared with those in intact forests. We also found an increase in condensed tannin content in drained forest trees, which may offset the drainage-induced acceleration of leaf decomposition to some extent.
{"title":"Drainage effects on leaf traits of trees in tropical peat swamp forests in Central Kalimantan, Indonesia","authors":"T. Ichie, Aogu Yoneyama, T. Hashimoto, Ayumi Tanaka‐Oda, K. Kusin, T. Kenzo","doi":"10.3759/TROPICS.MS18-12","DOIUrl":"https://doi.org/10.3759/TROPICS.MS18-12","url":null,"abstract":"Large areas of the tropical peat swamp forests in Central Kalimantan were drained to be converted into rice fields and then abandoned. A change in the soil water level due to drainage in the forests must have had a big impact on the ecology and ecophysiology of the trees in the drained remnant forests. The leaf traits of these trees in particular may have been directly or indirectly affected by drainage because of their high sensitivity to environmental change. To understand the influence of drainage on leaf traits, we investigated leaf morphological and physiological differences between intact and drained peat swamp forests in Palangka Raya, Indonesia, using 14 species distributed over both types of forests. We compared the leaf mass per unit area (LMA), leaf toughness, leaf area- and mass-based nitrogen content (N area and N mass ), carbon/nitrogen ratio, total phenolics, condensed tannin and lignin content and carbon isotope ratio ( δ 13 C) of both types of forest trees. In the drained forest, trees had higher values in LMA, N area , and δ 13 C than in the intact forest, suggesting that such trees adjust themselves to dry conditions to increase photosynthetic ability with high water use efficiency compared with those in intact forests. We also found an increase in condensed tannin content in drained forest trees, which may offset the drainage-induced acceleration of leaf decomposition to some extent.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41432270","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}
In Yoron Island, cultivation of Sugarcane makes up 52 % of the agriculture on the island, and it comes with extensive use of chemical fertilizers with ammonium sulfate. Moreover, as the main island is geographically formed from karst by the raised coral reef, precipitation smoothly flows to the sea through the underground. In this process, sulfate is brought to the sea as well. It is believed that potential hazards are then caused to the coral reef ecosystem. Considering this background, we aimed to evaluate the influence of sulfate on coral reef by analyzing the stable isotopes ratio of nitrogen ( δ 15 N) and sulfur ( δ 34 S). Since the δ 34 S of sulfate is 0 ‰ , the same value would also be shown in coral skeleton if there were significant effect of inflows. Our result reveals that δ 15 N value in coral skeleton is similar to that of the chemical fertilizer. A contrary, δ 34 S value obtained did not show similarity with that of the sulfate. However, from the analysis of the δ 34 S in growth ring, we witness a decrease of 2 ‰ to 5 ‰ from 1979 to 2013 and from 1990 to 2013. The conclusive result is that the δ 34 S value in coral skeleton is not significantly affected by that of the value of sulfate fertilizer. Nonetheless, the consistent decrease of δ 34 S from 1979 to 2013 may possibly be related to the increase of inflow of land-substance with low δ 34 S value to the sea.
{"title":"Stable isotope study on nitrogen and sulfur impact to coral ecosystem of Yoron, Japan","authors":"Yuya Otani, Y. Nakanishi","doi":"10.3759/TROPICS.MS18-04","DOIUrl":"https://doi.org/10.3759/TROPICS.MS18-04","url":null,"abstract":"In Yoron Island, cultivation of Sugarcane makes up 52 % of the agriculture on the island, and it comes with extensive use of chemical fertilizers with ammonium sulfate. Moreover, as the main island is geographically formed from karst by the raised coral reef, precipitation smoothly flows to the sea through the underground. In this process, sulfate is brought to the sea as well. It is believed that potential hazards are then caused to the coral reef ecosystem. Considering this background, we aimed to evaluate the influence of sulfate on coral reef by analyzing the stable isotopes ratio of nitrogen ( δ 15 N) and sulfur ( δ 34 S). Since the δ 34 S of sulfate is 0 ‰ , the same value would also be shown in coral skeleton if there were significant effect of inflows. Our result reveals that δ 15 N value in coral skeleton is similar to that of the chemical fertilizer. A contrary, δ 34 S value obtained did not show similarity with that of the sulfate. However, from the analysis of the δ 34 S in growth ring, we witness a decrease of 2 ‰ to 5 ‰ from 1979 to 2013 and from 1990 to 2013. The conclusive result is that the δ 34 S value in coral skeleton is not significantly affected by that of the value of sulfate fertilizer. Nonetheless, the consistent decrease of δ 34 S from 1979 to 2013 may possibly be related to the increase of inflow of land-substance with low δ 34 S value to the sea.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS18-04","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44003444","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}
Three specimens of Egesina ( Callienispia ) elegans (Fisher, 1925) are first recorded since 1925 as the first representative from East Kalimantan, Indonesia with detail description, fine quality figures, and brief notes.
{"title":"New Locality Record and Notes on Egesina (Callienispia) elegans from East Kalimantan, Indonesia (Insecta, Coleoptera, Cerambycidae, Lamiinae)","authors":"Sugiarto, J. Yamasako, H. Makihara, T. Toma","doi":"10.3759/tropics.ms18-11","DOIUrl":"https://doi.org/10.3759/tropics.ms18-11","url":null,"abstract":"Three specimens of Egesina ( Callienispia ) elegans (Fisher, 1925) are first recorded since 1925 as the first representative from East Kalimantan, Indonesia with detail description, fine quality figures, and brief notes.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48863083","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}
Twenty years of long-term maize monoculture that began in the 1990s have resulted in the heavily maizedependent economy of the northwestern mountainous region of Vietnam, especially in Yen Chau, the core production area. Before 2014, maize accounted for over 70 % of the agricultural area. The continuous decrease in maize production value has strongly affected the Tai Dam community in Yen Chau and led to the replacement of various livelihood activities. This contributed to a major shrinkage of the maize area by 28.2 % by the end of 2017. This study aims to investigate the determinants of the rapid development of different livelihood trends in Lac Ken, Suoi Bun, and Luong Me villages. A detailed social and statistical investigation was conducted of 198 households in 2016 and 220 households in 2017. The findings of this study indicate that small differences in cultivated land areas and infrastructure facilities have fostered the formation of and changes in livelihood structures. The areal withdrawal of maize occurred concurrently with the increasing trend of fruit tree and sugarcane cultivation. Neverbefore-seen migrant work unexpectedly became a promising livelihood activity for local farmers. Differences in internal and external forces are believed to be the driving factors behind the new forms of livelihood activities.
{"title":"Driving forces for livelihood structure changes in Vietnam’s northwestern mountainous region: A case study on Yen Chau district, Son La province","authors":"N. Ngọc, S. Yokoyama","doi":"10.3759/TROPICS.MS18-09","DOIUrl":"https://doi.org/10.3759/TROPICS.MS18-09","url":null,"abstract":"Twenty years of long-term maize monoculture that began in the 1990s have resulted in the heavily maizedependent economy of the northwestern mountainous region of Vietnam, especially in Yen Chau, the core production area. Before 2014, maize accounted for over 70 % of the agricultural area. The continuous decrease in maize production value has strongly affected the Tai Dam community in Yen Chau and led to the replacement of various livelihood activities. This contributed to a major shrinkage of the maize area by 28.2 % by the end of 2017. This study aims to investigate the determinants of the rapid development of different livelihood trends in Lac Ken, Suoi Bun, and Luong Me villages. A detailed social and statistical investigation was conducted of 198 households in 2016 and 220 households in 2017. The findings of this study indicate that small differences in cultivated land areas and infrastructure facilities have fostered the formation of and changes in livelihood structures. The areal withdrawal of maize occurred concurrently with the increasing trend of fruit tree and sugarcane cultivation. Neverbefore-seen migrant work unexpectedly became a promising livelihood activity for local farmers. Differences in internal and external forces are believed to be the driving factors behind the new forms of livelihood activities.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS18-09","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47014808","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}
While the canopy layer shows the highest productivity in forests, it also has the highest herbivore population density. How do canopy trees cope with attack from herbivores under such conditions? We investigated the relationship between leaf flushing phenology, defensive and photosynthetic traits, such as leaf flushing frequency, the number of emerging leaves per flushing term, the leaf life span, total phenolic and condensed tannin contents, leaf toughness, leaf nitrogen content, the photosynthetic rate at light saturation (Pmax) and leaf mass per area (LMA), in canopy trees of five dipterocarp species in a Malaysian tropical rain forest. Interspecific variations were clearly observed in leaf flushing frequency, ranging from occasional to continuous patterns. The total phenolic content significantly increased with leaf flushing frequency. Leaf toughness showed no correlation with leaf flushing phenology, but species with occasional leaf flushing had greater leaf toughness than those with continuous leaf production. There was a negative correlation between leaf toughness and tannin content, and a positive correlation between the former and Pmax. In addition, the leaf herbivory rate significantly increased with a larger number of emerging leaves per term and a higher comprehensive index (PC1) from PCA analysis using leaf flushing frequency and the number of leaves. Therefore, our results suggest that tropical canopy species have various defensive strategies against herbivore attack by regulating the intensity of chemical, physical and phenological defenses; species with high leaf flushing frequency have more chemically defended leaves, while those with low leaf flushing frequency have tougher leaves with higher photosynthetic abilities.
{"title":"Relationship between leaf flushing phenology and defensive traits of canopy trees of five dipterocarp species in a tropical rain forest","authors":"Aogu Yoneyama, T. Ichie","doi":"10.3759/TROPICS.MS18-13","DOIUrl":"https://doi.org/10.3759/TROPICS.MS18-13","url":null,"abstract":"While the canopy layer shows the highest productivity in forests, it also has the highest herbivore population density. How do canopy trees cope with attack from herbivores under such conditions? We investigated the relationship between leaf flushing phenology, defensive and photosynthetic traits, such as leaf flushing frequency, the number of emerging leaves per flushing term, the leaf life span, total phenolic and condensed tannin contents, leaf toughness, leaf nitrogen content, the photosynthetic rate at light saturation (Pmax) and leaf mass per area (LMA), in canopy trees of five dipterocarp species in a Malaysian tropical rain forest. Interspecific variations were clearly observed in leaf flushing frequency, ranging from occasional to continuous patterns. The total phenolic content significantly increased with leaf flushing frequency. Leaf toughness showed no correlation with leaf flushing phenology, but species with occasional leaf flushing had greater leaf toughness than those with continuous leaf production. There was a negative correlation between leaf toughness and tannin content, and a positive correlation between the former and Pmax. In addition, the leaf herbivory rate significantly increased with a larger number of emerging leaves per term and a higher comprehensive index (PC1) from PCA analysis using leaf flushing frequency and the number of leaves. Therefore, our results suggest that tropical canopy species have various defensive strategies against herbivore attack by regulating the intensity of chemical, physical and phenological defenses; species with high leaf flushing frequency have more chemically defended leaves, while those with low leaf flushing frequency have tougher leaves with higher photosynthetic abilities.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS18-13","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49630892","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}
Communities in Myanmar rely heavily on forests for various uses, but there have been few studies on disturbance to tropical evergreen forests in the country. There is a growing need to evaluate the responses after disturbances relating to soil condition to inform sustainable forest management practices to all regulating agencies. This study assessed the impact of forest disturbances on soil properties in a tropical evergreen forest ecosystem in Myanmar. Soil samples were collected from the sites with three different types of forest disturbance, namely 1) shifting cultivation (≥15 years post-abandonment), 2) landslide (20 years post-landslide), 3) selective logging ( ＞ 30 years post-logging), and 4) old growth forest (no recorded history of disturbance over the last 80 years), to determine the effects of forest disturbances on soil carbon (C), nitrogen (N), available phosphorus (AP), pH, and bulk density (BD). Soil C, N, and AP concentrations were significantly higher in old growth forest soils than in the other disturbed forests, while BD was lowest in old growth forest soils. There were no significant differences in soil properties between soil depths, except in BD. Selective logging area soils had the lowest C, N, and pH values, and AP may be severely depleted in areas of shifting cultivation. Our results confirm that forest disturbances can alter soil properties and that the impacts differ among forest disturbance types. Forest areas were slashed and burned for cultivation, cleared by landslides, and selectively logged during harvesting time, and after abandonment, the soil conditions determined the recovery pattern of the forest. According to our results, a logging cycle of more than 30 years is essential to mitigate the influences
{"title":"Impact of forest disturbances on soil properties: a case study in Mon State, Myanmar","authors":"Ei Thandar Bol, N. Tokuchi","doi":"10.3759/TROPICS.MS16-18","DOIUrl":"https://doi.org/10.3759/TROPICS.MS16-18","url":null,"abstract":"Communities in Myanmar rely heavily on forests for various uses, but there have been few studies on disturbance to tropical evergreen forests in the country. There is a growing need to evaluate the responses after disturbances relating to soil condition to inform sustainable forest management practices to all regulating agencies. This study assessed the impact of forest disturbances on soil properties in a tropical evergreen forest ecosystem in Myanmar. Soil samples were collected from the sites with three different types of forest disturbance, namely 1) shifting cultivation (≥15 years post-abandonment), 2) landslide (20 years post-landslide), 3) selective logging ( ＞ 30 years post-logging), and 4) old growth forest (no recorded history of disturbance over the last 80 years), to determine the effects of forest disturbances on soil carbon (C), nitrogen (N), available phosphorus (AP), pH, and bulk density (BD). Soil C, N, and AP concentrations were significantly higher in old growth forest soils than in the other disturbed forests, while BD was lowest in old growth forest soils. There were no significant differences in soil properties between soil depths, except in BD. Selective logging area soils had the lowest C, N, and pH values, and AP may be severely depleted in areas of shifting cultivation. Our results confirm that forest disturbances can alter soil properties and that the impacts differ among forest disturbance types. Forest areas were slashed and burned for cultivation, cleared by landslides, and selectively logged during harvesting time, and after abandonment, the soil conditions determined the recovery pattern of the forest. According to our results, a logging cycle of more than 30 years is essential to mitigate the influences","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS16-18","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70009826","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}
Reduced impact logging (RIL) is a challenge to mitigate detrimental effects of selective logging, which is known to mitigate C losses as timbers and forest degradation. Although it was predicted that RIL can also mitigate non-CO 2 greenhouse gas fluxes through reduced disturbances, the reality has been rarely reported. In the present study, we conducted a preliminary research on N 2 O and CH 4 fluxes in a 2-ha plot in each of primary, RIL and conventional logging (CL) forest in Bornean lowland tropical rain forests. The results showed that CL significantly enhanced N 2 O emissions, but N 2 O emissions from the RIL forest did not differ from those from the primary forest, suggesting that RIL can mitigate N 2 O emissions enhanced by CL. On the other hand, CH 4 fluxes were not significantly different among three forest types.
{"title":"A preliminary report: does reduced impact logging (RIL) mitigate non-CO 2 greenhouse gas emissions from natural production forests?","authors":"Taiki Mori, N. Imai, K. Kitayama","doi":"10.3759/TROPICS.MS17-08","DOIUrl":"https://doi.org/10.3759/TROPICS.MS17-08","url":null,"abstract":"Reduced impact logging (RIL) is a challenge to mitigate detrimental effects of selective logging, which is known to mitigate C losses as timbers and forest degradation. Although it was predicted that RIL can also mitigate non-CO 2 greenhouse gas fluxes through reduced disturbances, the reality has been rarely reported. In the present study, we conducted a preliminary research on N 2 O and CH 4 fluxes in a 2-ha plot in each of primary, RIL and conventional logging (CL) forest in Bornean lowland tropical rain forests. The results showed that CL significantly enhanced N 2 O emissions, but N 2 O emissions from the RIL forest did not differ from those from the primary forest, suggesting that RIL can mitigate N 2 O emissions enhanced by CL. On the other hand, CH 4 fluxes were not significantly different among three forest types.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS17-08","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70009969","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, Thy Sum
Dead organic matter (DOM), which includes deadwood (DW) and litter (LT), plays an important role in forest ecosystem functions. To date, little DOM data have been collected in the seasonal forests of Indochina. We monitored DW and LT masses in Cambodian seasonal forests during a period of 10 years at intervals of 1‒2 years in 22 permanent sample plots (PSPs) in evergreen forest (EF, n=10) and deciduous forest (DF, n=12) deployed across Cambodia. We found that large aboveground biomass (AGB) loss events, which were probably caused by logging, increased DW mass and DOM carbon stock. However, such AGB loss events did not necessarily affect LT masses (i.e., coarse LT [CLT] and fine LT including partly decomposed roots to a soil depth of 5 cm [FLT]). The mean DOM carbon stock and masses of DW, LT, CLT, and FLT during the study period had no significant relationships with AGB in either EF or DF. DOM and its components exhibited large spatial variations, suggesting that additional sampling is required for greater precision. The Cambodian seasonal forest was characterized by a relatively small DW mass, possibly due to anthropogenic removal of DW and dying trees.
{"title":"Effects of large aboveground biomass loss events on the deadwood and litter mass dynamics of seasonal tropical forests in Cambodia","authors":"Y. Kiyono, Eriko Ito, Yukako Monda, Jumpei Toriyama, Thy Sum","doi":"10.3759/TROPICS.MS18-05","DOIUrl":"https://doi.org/10.3759/TROPICS.MS18-05","url":null,"abstract":"Dead organic matter (DOM), which includes deadwood (DW) and litter (LT), plays an important role in forest ecosystem functions. To date, little DOM data have been collected in the seasonal forests of Indochina. We monitored DW and LT masses in Cambodian seasonal forests during a period of 10 years at intervals of 1‒2 years in 22 permanent sample plots (PSPs) in evergreen forest (EF, n=10) and deciduous forest (DF, n=12) deployed across Cambodia. We found that large aboveground biomass (AGB) loss events, which were probably caused by logging, increased DW mass and DOM carbon stock. However, such AGB loss events did not necessarily affect LT masses (i.e., coarse LT [CLT] and fine LT including partly decomposed roots to a soil depth of 5 cm [FLT]). The mean DOM carbon stock and masses of DW, LT, CLT, and FLT during the study period had no significant relationships with AGB in either EF or DF. DOM and its components exhibited large spatial variations, suggesting that additional sampling is required for greater precision. The Cambodian seasonal forest was characterized by a relatively small DW mass, possibly due to anthropogenic removal of DW and dying trees.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS18-05","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010641","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}
Radial variation of δ 18 O before and after cellulose extraction was assessed in Acacia auriculiformis , Eucalyptus camaldulensis , and Celtis timorensis growing in northeastern Thailand to examine the necessity of extracting α -cellulose to detect annual rings from trees without visible rings. Optimum sampling resolution to detect peaks in the radial variation of δ 18 O values was also examined. Cored samples were sectioned into 0.2 mm thickness in the radial direction. Each circular section sliced from a wood core sample were divided along wood grain into two semicircular sections, both of which were located at the same radial and longitudinal positions, and were side-by-side tangentially. One half was used for bulk analysis and the other for extraction. Peak positions were assigned from the seasonal variation of δ 18 O. The δ 18 O values cyclically changed in both bulk wood and α -cellulose. The correlation coefficient between bulk wood and α -cellulose δ 18 O was high in every species, and the offset was almost constant across the radial position. The mean cycle length of one sample was longer than those of the other two samples, although annual increment based on dendrometer monitoring was smaller than those of the other two samples. That is, the seasonal variation in δ 18 O values recorded in the xylem was not completely detected because of low amplitude or insufficient radial resolution. Therefore, we concluded that α -cellulose extraction is unnecessary for annual ring detection. It is necessary to determine an appropriate sampling resolution based on growth rate for effective peak detection.
{"title":"Sample preparation of ring-less tropical trees for δ18O measurement in isotope dendrochronology","authors":"W. Nakai, Naoki Okada, M. Sano, T. Nakatsuka","doi":"10.3759/TROPICS.MS17-09","DOIUrl":"https://doi.org/10.3759/TROPICS.MS17-09","url":null,"abstract":"Radial variation of δ 18 O before and after cellulose extraction was assessed in Acacia auriculiformis , Eucalyptus camaldulensis , and Celtis timorensis growing in northeastern Thailand to examine the necessity of extracting α -cellulose to detect annual rings from trees without visible rings. Optimum sampling resolution to detect peaks in the radial variation of δ 18 O values was also examined. Cored samples were sectioned into 0.2 mm thickness in the radial direction. Each circular section sliced from a wood core sample were divided along wood grain into two semicircular sections, both of which were located at the same radial and longitudinal positions, and were side-by-side tangentially. One half was used for bulk analysis and the other for extraction. Peak positions were assigned from the seasonal variation of δ 18 O. The δ 18 O values cyclically changed in both bulk wood and α -cellulose. The correlation coefficient between bulk wood and α -cellulose δ 18 O was high in every species, and the offset was almost constant across the radial position. The mean cycle length of one sample was longer than those of the other two samples, although annual increment based on dendrometer monitoring was smaller than those of the other two samples. That is, the seasonal variation in δ 18 O values recorded in the xylem was not completely detected because of low amplitude or insufficient radial resolution. Therefore, we concluded that α -cellulose extraction is unnecessary for annual ring detection. It is necessary to determine an appropriate sampling resolution based on growth rate for effective peak detection.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS17-09","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010591","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}
Takaharu Mochizuki, Dokrak Marod, Dang Thinh Trieu, H. Mizunaga
Differences in light capture strategies of tropical monsoon trees were examined with a focus on the function of hierarchical leaf cluster structure. Specifically, morphological differences in leaf clusters were examined among ecological functional groups of tree species. The three-dimensional distribution of leaves within 62 crowns of 21 species in or above the canopy layer was estimated using a terrestrial laser scanner. Leaf clusters with hierarchical structure were identified within each crown, and the thickness and inclination of a leaf cluster were calculated. The light capture property of the crown was examined using the light extinction coefficient and the directional dependency of light capture. An ordination technique was used to organize crown architecture into two axes: one corresponding to the directional dependency of light capture, which separates leaf phenological types, and the other representing the spatial scale contributing to light capture, which separates growth forms. Similar leaf cluster shapes at various spatial levels ranging from small leaf clusters to crowns caused specialization of crown directional dependency, which was clearest in emergent species. In deciduous species, flatter leaf clusters at various spatial levels were specialized to efficiently capture overhead light, whereas rounder leaf clusters at various spatial levels in evergreen species were specialized to uniform light capture from all directions. Different light capture strategies among functional groups in tropical monsoon forest would be related to drought stress response.
{"title":"Interspecific differences in the hierarchical cluster structure of leaves within tree crowns in Indochina","authors":"Takaharu Mochizuki, Dokrak Marod, Dang Thinh Trieu, H. Mizunaga","doi":"10.3759/TROPICS.MS17-07","DOIUrl":"https://doi.org/10.3759/TROPICS.MS17-07","url":null,"abstract":"Differences in light capture strategies of tropical monsoon trees were examined with a focus on the function of hierarchical leaf cluster structure. Specifically, morphological differences in leaf clusters were examined among ecological functional groups of tree species. The three-dimensional distribution of leaves within 62 crowns of 21 species in or above the canopy layer was estimated using a terrestrial laser scanner. Leaf clusters with hierarchical structure were identified within each crown, and the thickness and inclination of a leaf cluster were calculated. The light capture property of the crown was examined using the light extinction coefficient and the directional dependency of light capture. An ordination technique was used to organize crown architecture into two axes: one corresponding to the directional dependency of light capture, which separates leaf phenological types, and the other representing the spatial scale contributing to light capture, which separates growth forms. Similar leaf cluster shapes at various spatial levels ranging from small leaf clusters to crowns caused specialization of crown directional dependency, which was clearest in emergent species. In deciduous species, flatter leaf clusters at various spatial levels were specialized to efficiently capture overhead light, whereas rounder leaf clusters at various spatial levels in evergreen species were specialized to uniform light capture from all directions. Different light capture strategies among functional groups in tropical monsoon forest would be related to drought stress response.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS17-07","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70009903","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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