【摘 要】
：
Tree-ring δ15N has been frequently used to reveal the historical emissions of anthropogenic N,the changes in forest N cycle and in plant N availability.The homogeneities of tree-ring δ15N,which were o
【机 构】
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South China Botanical Garden,Chinese Academy of Sciences,Guangzhou,510650,China
【出 处】
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International Symposium on Forest Soils(2013年森林土壤国际研讨会)
论文部分内容阅读
Tree-ring δ15N has been frequently used to reveal the historical emissions of anthropogenic N,the changes in forest N cycle and in plant N availability.The homogeneities of tree-ring δ15N,which were of the most importance in above research,among different aged tree species from the same and different sites were seldom concerned up to date.In this study,the patterns of tree-ring δ15N over time in southern China were used to test whether they were species and age dependent.At the same sampling site,tree-ring δ15N progressively increased against the time for Cinnamomun camphora,a broadleaf species,with positive values.while progressively decreased for Pinus massoniana,a coniferous species,with many negative values.Contrast patterns of tree-ring 85N between two species from the same site suggested they may use different soil N sources.Within the same species,tree-ring δ15N in Pinus kwangtungensis(also coniferous)patterned heterogeneously in different aged trees.In the older tree,tree-ring δ15N were negatively fluctuated against the time.In the younger one,however,tree-ring δ15N increased progressively with positive values.At the different sites.the same tree species(Pinus massoniana)presented the similar tree-ring δ15N patterns significantly decreasing over the time.Our results in the present study demonstrated that patterns of tree-ring δ15N are species-and age-specific.Thus in the future,the species-and age-depended tree-ring δ15N should be carefully taken into consideration in the stable dendro-isotopic chronology research.
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