Global climate change can affect tree growth and carbon sink function by influencing plant carbohydrate synthesis and utilization,while elevation can be used as an ideal setting under natural conditions to simulate cl...Global climate change can affect tree growth and carbon sink function by influencing plant carbohydrate synthesis and utilization,while elevation can be used as an ideal setting under natural conditions to simulate climate change effects.The effect of elevation on tree growth may depend on organ type.However,the allocation patterns of nonstructural and structural carbohydrates(NSCs and SCs,respectively)in different tree organs and their response to elevation remain unclear.We selected four dominant tree species,Schima superba,Castanopsis eyrei,Castanopsis fargesii and Michelia maudiae,along an elevation gradient from 609 to 1,207 m in subtropical evergreen broad-leaved forests and analyzed leaf,trunk,and fine root NSCs,carbon(C),nitrogen(N)and phosphorus(P)concentrations and the relative abundance of SCs.Leaf NSCs increased initially and then decreased,and trunk NSCs increased with increasing elevation.However,root NSCs decreased with increasing elevation.The relative abundance of SCs in leaves and trunks decreased,while the relative abundance of root SCs increased with increasing elevation.No significant correlations between SCs and NSCs in leaves were detected,while there were negative correlations between SCs and NSCs in trunks,roots,and all organs.Hierarchical partitioning analysis indicated that plant C/N and C/P were the main predictors of changes in SCs and NSCs.Our results suggest that tree organs have divergent responses to elevation and that increasing elevation will inhibit the aboveground part growth and enhance the root growth of trees.A tradeoff between the C distribution used for growth and storage was confirmed along the elevation gradient,which is mainly manifested in the"sink"organs of NSCs.Our results provide insight into tree growth in the context of global climate change scenarios in subtropical forest ecosystems.展开更多
Forests over limestone in the tropics have received little attention and limestone forests in Vietnam have been overlooked to an even greater extent in terms of tree physiology. In Ba Be National Park, Vietnam, soil w...Forests over limestone in the tropics have received little attention and limestone forests in Vietnam have been overlooked to an even greater extent in terms of tree physiology. In Ba Be National Park, Vietnam, soil water availability in limestone forests seems to be the most limiting factor in the dry season. Therefore, in order to enhance the preliminary knowledge of choosing native tree species for enrichment planting in the restoration zone, characteristics of the 20 native tree species to soil water stress were investigated in a limestone forest. One-ha plot each consisting of twenty-five 20 m × 20 m plots was established in undisturbed forests. All trees ≥ 10 cm DBH were measured in 20 m × 20 m plots, while twenty-five 5 m × 5 m subplots were established in order to sample the regeneration of tree species with a DBH < 10 cm. The Scholander apparatus and freezing point osmometry were used in order to measure the leaf water potential (Ψw) and leaf osmotic potential (Ψπ) of the 20 native tree species, respectively in this study. 61 species belonging to 34 families of all trees with a DBH ≥ 10 cm were recorded in one ha, while 31 species representing 18 families of trees < 10 cm DBH were identified in 625 m2. The 20 species’ leaf water and osmotic potential values revealed significant differences among species. The maximum leaf water potential was not affected by any anticipated sources of variation, while the minimum water potential, however, showed significant variation to soil water stress. The results in the study area emphasized the importance of water factors in influencing tree species distribution;it could be concluded that native species with wide water potential ranges would be better able to withstand water changes and might be thus good candidates for reforestation (enrichment planting) in limestone areas.展开更多
Independent XML storage based on XSD (XML Schema Document) is adopted in NXD(Native XML Database), XML storage structure based on tree-structure disassemble and the algorithm used in dynamically updating XML document ...Independent XML storage based on XSD (XML Schema Document) is adopted in NXD(Native XML Database), XML storage structure based on tree-structure disassemble and the algorithm used in dynamically updating XML document are provided in this paper. The main idea is that in term of data model of XML document, XML document is parsed to Document Structure-Tree with Hierarchical Model and Leaf-Data with Relation Model for storage. Simultaneously Proxy node is imported in order to solve the problem that XML data store in cross-blocks. And with XSD model information, sparse index is constructed to save storage space. It is proved that this storage structure could improve efficiency of XML document operation.展开更多
A 10 ha deciduous seasonal forest fragment (15°45'54''S and 49°04'03''W) found in the bioregion of the Savanna Eco Museum localized in the state of Goiás, Brazil was studied. For...A 10 ha deciduous seasonal forest fragment (15°45'54''S and 49°04'03''W) found in the bioregion of the Savanna Eco Museum localized in the state of Goiás, Brazil was studied. For the phytosociological survey, 10 sample plots of 20 × 20 m were systematically located. All living trees of 5 cm DBH and above were measured with the plot boundaries. There were 742 individuals belonging to 83 species and 38 families. The richest families in terms of the number of species were Leguminosae, Rubiaceae, Myrtaceae, Apocynaceae and Chrisobalanaceae, which contributed 48% of the total species. The species with the highest importance value indices (IVI) were Tapira quianensis (Aubl.), Protium heptaphyllum (Aubl.) March., Callisthene mayor (Mart.), Amaioua guianensis (Aubl.) and Anadenanthera macrocarpa (Benth.) Brenan. The Shannon diversity index was 3.80 nats/individuals and the Pielou equality index was 0.86 for the total population. 549 sampled trees had DBH values lower than 30 cm. This indicates that this forest has a high potential for natural succession. Two DBH distributions were observed: the typical reverse “J”, described frequently in the literature, and a nearly Gaussian distribution.展开更多
基金the National Natural Science Foundation of China(32260379&32371852)the Jiangxi Provincial Natural Science Foundation(20224ACB215005)
文摘Global climate change can affect tree growth and carbon sink function by influencing plant carbohydrate synthesis and utilization,while elevation can be used as an ideal setting under natural conditions to simulate climate change effects.The effect of elevation on tree growth may depend on organ type.However,the allocation patterns of nonstructural and structural carbohydrates(NSCs and SCs,respectively)in different tree organs and their response to elevation remain unclear.We selected four dominant tree species,Schima superba,Castanopsis eyrei,Castanopsis fargesii and Michelia maudiae,along an elevation gradient from 609 to 1,207 m in subtropical evergreen broad-leaved forests and analyzed leaf,trunk,and fine root NSCs,carbon(C),nitrogen(N)and phosphorus(P)concentrations and the relative abundance of SCs.Leaf NSCs increased initially and then decreased,and trunk NSCs increased with increasing elevation.However,root NSCs decreased with increasing elevation.The relative abundance of SCs in leaves and trunks decreased,while the relative abundance of root SCs increased with increasing elevation.No significant correlations between SCs and NSCs in leaves were detected,while there were negative correlations between SCs and NSCs in trunks,roots,and all organs.Hierarchical partitioning analysis indicated that plant C/N and C/P were the main predictors of changes in SCs and NSCs.Our results suggest that tree organs have divergent responses to elevation and that increasing elevation will inhibit the aboveground part growth and enhance the root growth of trees.A tradeoff between the C distribution used for growth and storage was confirmed along the elevation gradient,which is mainly manifested in the"sink"organs of NSCs.Our results provide insight into tree growth in the context of global climate change scenarios in subtropical forest ecosystems.
基金support by the Open Access Publication Funds of the Gottingen University
文摘Forests over limestone in the tropics have received little attention and limestone forests in Vietnam have been overlooked to an even greater extent in terms of tree physiology. In Ba Be National Park, Vietnam, soil water availability in limestone forests seems to be the most limiting factor in the dry season. Therefore, in order to enhance the preliminary knowledge of choosing native tree species for enrichment planting in the restoration zone, characteristics of the 20 native tree species to soil water stress were investigated in a limestone forest. One-ha plot each consisting of twenty-five 20 m × 20 m plots was established in undisturbed forests. All trees ≥ 10 cm DBH were measured in 20 m × 20 m plots, while twenty-five 5 m × 5 m subplots were established in order to sample the regeneration of tree species with a DBH < 10 cm. The Scholander apparatus and freezing point osmometry were used in order to measure the leaf water potential (Ψw) and leaf osmotic potential (Ψπ) of the 20 native tree species, respectively in this study. 61 species belonging to 34 families of all trees with a DBH ≥ 10 cm were recorded in one ha, while 31 species representing 18 families of trees < 10 cm DBH were identified in 625 m2. The 20 species’ leaf water and osmotic potential values revealed significant differences among species. The maximum leaf water potential was not affected by any anticipated sources of variation, while the minimum water potential, however, showed significant variation to soil water stress. The results in the study area emphasized the importance of water factors in influencing tree species distribution;it could be concluded that native species with wide water potential ranges would be better able to withstand water changes and might be thus good candidates for reforestation (enrichment planting) in limestone areas.
基金Supported by the National Natural Science Foun-dation of China (60073045)
文摘Independent XML storage based on XSD (XML Schema Document) is adopted in NXD(Native XML Database), XML storage structure based on tree-structure disassemble and the algorithm used in dynamically updating XML document are provided in this paper. The main idea is that in term of data model of XML document, XML document is parsed to Document Structure-Tree with Hierarchical Model and Leaf-Data with Relation Model for storage. Simultaneously Proxy node is imported in order to solve the problem that XML data store in cross-blocks. And with XSD model information, sparse index is constructed to save storage space. It is proved that this storage structure could improve efficiency of XML document operation.
文摘A 10 ha deciduous seasonal forest fragment (15°45'54''S and 49°04'03''W) found in the bioregion of the Savanna Eco Museum localized in the state of Goiás, Brazil was studied. For the phytosociological survey, 10 sample plots of 20 × 20 m were systematically located. All living trees of 5 cm DBH and above were measured with the plot boundaries. There were 742 individuals belonging to 83 species and 38 families. The richest families in terms of the number of species were Leguminosae, Rubiaceae, Myrtaceae, Apocynaceae and Chrisobalanaceae, which contributed 48% of the total species. The species with the highest importance value indices (IVI) were Tapira quianensis (Aubl.), Protium heptaphyllum (Aubl.) March., Callisthene mayor (Mart.), Amaioua guianensis (Aubl.) and Anadenanthera macrocarpa (Benth.) Brenan. The Shannon diversity index was 3.80 nats/individuals and the Pielou equality index was 0.86 for the total population. 549 sampled trees had DBH values lower than 30 cm. This indicates that this forest has a high potential for natural succession. Two DBH distributions were observed: the typical reverse “J”, described frequently in the literature, and a nearly Gaussian distribution.
