Effects of drought on water use of seven tree species from four genera growing in a bottomland hardwood forest
Effects of drought on water use of seven tree species from four genera growing in a bottomland hardwood forest
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DOI：
10.1016/j.agrformet.2021.108353
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发表时间：
2021-05
影响因子：
6.2
通讯作者：
Z. Kassahun;H. Renninger
中科院分区：
文献类型：
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作者：
Z. Kassahun;H. Renninger
对于河滩森林，如滩地阔叶林，水分供应的巨大波动可能会导致来自洪水和干旱条件的压力。同样，这些森林的物种组成可能不同，共存物种的用水和干旱战略将影响周围的水文、营养动态和生产力。因此，本研究的目的是比较4个属(山核桃、水曲柳、栎树、榆树)在干旱和平均降雨年的水分利用、冠层气孔导度及其对环境驱动因素的响应。多年来，樱桃树、橡树和有翼榆树的用水量是相似的。与平均降雨年相比，在干旱年份，沼泽板栗、柳树和沙棘山核桃的用水量约为三分之二，美国榆树和白蜡树的用水量约为一半。不同物种对VPD的水分利用响应、冠层气孔导度参考值以及干旱和平均降雨年叶片衰老的时间也不同，这将根据干旱条件和物种组成影响生态系统过程。由于土壤饱和，山胡桃树、有翼榆树和沼泽板栗橡树表现出最大的水分利用下降。总体而言，物种在耐涝和耐旱以及最大水分利用潜力和耐旱性之间表现出权衡。总体而言，在干旱和非干旱年份，滩地阔叶林的用水量及其对环境驱动因素的响应的差异将取决于物种组成，这些发现有助于在温带泛滥平原森林中进行建模工作。
For floodplain forests such as bottomland hardwood forests, large fluctuations in moisture availability can lead to stress from both flooded as well as drought conditions. Likewise, these forests can be diverse in species composition and the water use and drought strategies of co-occurring species will impact surrounding hydrology, nutrient dynamics and productivity. Therefore, the objectives of this study were to compare water use, canopy stomatal conductance and its response to environmental drivers in co-occurring bottomland hardwood species from four genera (Carya, Fraxinus, Quercus, Ulmus) during a drought and average rainfall year. Water use was similar across years in cherrybark oak and winged elm. For swamp chestnut oak, willow oak and shagbark hickory water use was about two thirds in the drought year compared with the average rainfall year and in American elm and green ash it was about one half. Species also varied in their responses of water use to VPD, reference canopy stomatal conductance values, and the timing of leaf senescence during the drought and average rainfall year which will impact ecosystem processes based on drought conditions and species composition. Shagbark hickory, winged elm and swamp chestnut oak exhibited the most declines in water use due to soil saturation. In general, species exhibited a tradeoff between flood tolerance and drought tolerance as well as between maximal water use potential and drought tolerance. In total, differences in water use and its response to environmental drivers during drought and non-drought years for bottomland hardwood forests will depend on species composition and these findings can benefit modeling efforts in temperate floodplain forests.