Contribution of lianas to community-level canopy transpiration in a warm-temperate forest
Contribution of lianas to community-level canopy transpiration in a warm-temperate forest
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DOI：
10.1111/1365-2435.12881
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发表时间：
2017-09
影响因子：
5.2
通讯作者：
Ryuji Ichihashi;C. Chiu;H. Komatsu;T. Kume;Yoshinori Shinohara;M. Tateishi;K. Tsuruta;K. Otsuki-K.-Otsu
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文献类型：
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作者：
Ryuji Ichihashi;C. Chiu;H. Komatsu;T. Kume;Yoshinori Shinohara;M. Tateishi;K. Tsuruta;K. Otsuki-K.-Otsu
藤本植物（木本攀缘植物）比树木有更多的叶，相对于基面积或站立的生物量，和非常宽的导管，允许有效的水分运输。这些特征表明，藤本植物可能消耗更多的水分比例比树木通过蒸腾作用。尽管其潜在的重要性，研究人员只进行了有限的尝试，以评估藤本植物对森林水分动态的影响。2.在日本一个藤本植物丰富的暖温带森林中，我们用热耗散法对四种藤本植物和四种树木的树干液流进行了为期一年的测量，并估计了藤本植物对林分冠层蒸腾的贡献。3.基于校准测量水的吸收率从切割茎端，在藤本植物茎的实际液流（Fd）是几倍大于从原来的校准提供的方法估计。在该领域，藤本植物表现出平均2-4倍的Fd大于树木全年。除此差异外，两组Fd相对变化的昼夜和季节模式相似。藤本植物和乔木植物的全株蒸腾量（Qt）与地径均呈指数关系，藤本植物的Qt随地径的增加比乔木的Qt增加更陡。通过外推Qt和基部直径之间的关系，研究地块的库存数据，我们估计，藤本植物贡献了12.8%的年林分冠层蒸腾，而占2.3%的林分断面积，这可能反映了顶部沉重的架构藤本植物。4.我们的研究结果表明，藤本植物对森林水分动态的贡献可能是几倍以上的森林断面积。这意味着藤本植物丰度的略微增加可能对水动力学产生更大的影响，并且通过与树木竞争有限的水，森林的碳固存能力可能比预期的更大。这项研究强调了评估世界范围内森林中藤本植物对森林水分动态的相对重要性的必要性。本文受版权保护。All rights reserved.
Summary 1.Lianas (woody climbers) have a greater amount of leaves relative to basal area or standing biomass than trees, and very wide vessels that permit efficient water transport. These features suggest that lianas possibly consume proportionally more water through transpiration than trees. Despite their potential importance, researchers have made only limited attempts to evaluate effects of lianas on forest water dynamics. 2.We conducted sap flow measurements for 1 year using a thermal-dissipation method for four species each of lianas and trees in a liana-rich, warm-temperate forest in Japan and estimated the contribution of lianas to stand canopy transpiration. 3.Based on a calibration measuring water uptake rates from cut-stem ends, the actual sap flux (Fd) in liana stems was several times greater than those estimated from the original calibration provided for the method. In the field, lianas showed an average of 2–4 times greater Fd than trees throughout the year. Except for this difference, diurnal and seasonal patterns of relative changes of Fd were similar in both groups. The whole-plant transpiration (Qt) of sample plants were exponentially related to basal diameter for both lianas and trees; Qt of lianas increased more steeply with basal diameter than that of trees. By extrapolating the relationships between Qt and basal diameter to the inventory data of the study plot, we estimated that lianas contributed 12.8% to the annual stand canopy transpiration while comprising 2.3% of stand basal area, which probably reflected the top-heavy architecture of lianas. 4.Our results indicate that the contribution of lianas to forest water dynamics may be several times greater than their contribution to forest basal area. This implies that a slight increase of liana abundance might have greater effects on water dynamics and, through competitions with trees for limited water, the carbon sequestration capacity of forests than expected from the increase in basal area. This study underlines the necessity of evaluating the relative importance of lianas to forest water dynamics in forests worldwide. This article is protected by copyright. All rights reserved.