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首页> 外文期刊>Hydrology and Earth System Sciences >Forest decline caused by high soil water conditions in a permafrost region
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Forest decline caused by high soil water conditions in a permafrost region

机译：多年冻土区高土壤水分条件引起的森林退化

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In the permafrost region near Yakutsk, eastern Siberia, Russia, annualprecipitation (June–May) in 2005–2006 and 2006–2007 exceeded the 26-year(1982–2008) mean of 222±68 mm by 185 mm and 128 mm, respectively,whereas in 2007–2008 the excedent was only 48 mm, well within the range ofvariability. Yellowing and browning of larch (Larix cajanderi Mayr.) trees occurred in anundisturbed forest near Yakutsk in the 2007 summer growing season. Soilwater content at a depth of 0.20 m was measured along a roughly 400 m longline transect running through areas of yellowing and browning larch trees(YBL) and of normal larch trees (NL). In the two years of supranormalprecipitation, soil water content was very high compared to valuesrecorded for the same area in previous studies. For both wet years, the meandegree of saturation (s) was significantly greater in YBL than NL areas,whereas the converse was the case for the gas diffusivity in soil. Thisimplies that rather than mitigating water stress suffered during normalprecipitation years, elevated soil water conditions adversely affected thegrowth of larch trees. Eastern Siberia's taiga forest extends widely intothe permafrost region. Was such supranormal annual precipitation to extendfor more than two years, as might be expected under impending global climatechanges, forest recovery may not be expected and emission of greenhouse gasmight continue in future.
机译：在俄罗斯西伯利亚东部雅库茨克附近的多年冻土地区，2005-2006年和2006-2007年（六月至五月）的年降水量分别超过26年（1982-2008年）的平均值222±68 mm 185mm和128mm。 ，而在2007-2008年，该赋形剂仅为48毫米，处于变异范围之内。 2007年夏季的生长季节，雅库茨克附近一片茂密的森林中发生了落叶松（ Larix cajanderi Mayr。）树木的泛黄和褐变。沿着大约400 m的延绳交界线测量了0.20 m深度的土壤水分，该交界线穿过发黄变褐的落叶松树木（YBL）和正常的落叶松树木（NL）。与过去研究中相同地区记录的值相比，在超常降水的两年中，土壤含水量非常高。在这两个潮湿年份，YBL的平均饱和度（ s ）显着大于NL地区，而土壤中气体扩散率则相反。这意味着升高的土壤水分状况并没有减轻正常降水年所遭受的水分胁迫，反而对落叶松的生长产生了不利影响。西伯利亚东部的针叶林森林广泛地延伸到永久冻土地区。如此超常的年降水量会持续两年以上，正如全球气候变化即将发生时所预期的那样，森林恢复可能无法预期，温室气体的排放可能会在未来继续。

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