Effects of spatial and temporal variability in soil moisture on widths and δ13C values of eastern Siberian tree rings
Effects of spatial and temporal variability in soil moisture on widths and δ13C values of eastern Siberian tree rings
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土壤湿度时空变化对东西伯利亚树木年轮宽度和δ13C值的影响
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
T. Maximov
中科院分区：
文献类型：
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作者：
A. Kagawa;D. Naito;A. Sugimoto;T. Maximov
[1]研究了西伯利亚东部雅库茨克地区干旱和湿润条件下早材/晚材宽度、纤维素稳定碳同位素比值（δ 13 C）与土壤水分之间的关系。春季融雪和夏季干旱对土壤水分的补给，使早材和晚材形成期的土壤水分状况形成了明显的季节性对比。年轮指数的计算方法是将每个早材/晚材宽度除以每个个体的5年平均宽度。为了确定干旱是否影响了年轮指数-δ 13 C关系，将年轮指数时间序列与δ 13 C时间序列进行了比较。本文采集了8个落叶松（Larix gmelinii（Rupr.）Rupr.和4株樟子松（Pinus sylvestris L.）测定了1996-2000年形成的早材和晚材宽度和δ 13 C值。在干旱地区，土壤含水量的季节变化与树木年轮δ 13 C的季节变化相对应。在以松属为主的干燥立地上，两种树种晚材的年轮指数与δ 13 C呈负相关，而在以落叶松为主的湿润立地上，落叶松晚材的年轮指数与δ 13 C无相关性。干旱条件下晚材生长的减少和/或提前停止以及δ 13 C的增加可能解释了这种负相关。这表明干旱对该地区树木生长的限制作用，以及利用干地晚木δ 13 C重建过去干旱的前景。
[1] We studied the relationships between earlywood/latewood width, stable carbon isotope ratio (δ13C) of cellulose, and soil moisture at a dry and a wet site in Yakutsk, eastern Siberia, which differed considerably in soil water conditions. Recharge of soil water by snowmelt in spring and subsequent drought in summer provided a marked seasonal contrast in soil water conditions between the earlywood and latewood formation period. Ring index was calculated by dividing each earlywood/latewood width by the 5-year averaged width for each individual. In order to determine whether drought influenced the ring index-δ13C relation, the ring index time series were compared with δ13C time series. We collected wood samples from eight Larix gmelinii (Rupr.) Rupr. and four Pinus sylvestris L. trees from the two sites and measured the earlywood and latewood widths and δ13C of earlywood and latewood formed during the years 1996–2000. At the dry site, seasonal soil water content variation corresponded to seasonal δ13C variation of tree rings. We found negative ring index-δ13C correlations in latewood for both species at the dry site mainly dominated by Pinus but not in latewood of Larix at the wet site dominated by Larix. Decrease and/or early cessation of latewood growth and increase in δ13C under drought conditions possibly explain this negative correlation. This suggests the growth limitation of trees in this region by drought and the prospects of reconstructing past drought with latewood δ13C of the dry site.