Rapid tree water transport and residence times in a Pennsylvania catchment: Rapid Tree Water Transport and Residence Times
Rapid tree water transport and residence times in a Pennsylvania catchment: Rapid Tree Water Transport and Residence Times
复制标题
宾夕法尼亚州流域的快速树木水输送和停留时间：快速树木水输送和停留时间
DOI：
10.1002/eco.1747
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发表时间：
2016
期刊：
影响因子：
2.6
通讯作者：
Eissenstat, David M.
中科院分区：
文献类型：
--
作者：
Gaines, Katie P.;Meinzer, Frederick C.;Duffy, Christopher J.;Thomas, Evan M.;Eissenstat, David M.
树木负责陆地上大部分降水的循环，并会影响土壤储水、溪流和地下水补给。从历史上看，美国东部森林的水资源并不经常受到限制。因此，很少有工作来了解这些系统中植被的用水时间。我们使用氘示踪剂、液流通量和解剖技术来研究宾夕法尼亚州中部森林覆盖的山脊顶部的树木水分输送。研究了每种主要环孔树种的三棵树：毛山核桃（山核桃山核桃）、栎树（板栗橡树）和红栎（红橡树）以及散孔糖枫（糖槭树）。我们假设环状多孔物种的示踪剂速度会更高，因为它们的容器直径更大，水传输效率更高，但示踪剂停留时间在很大程度上取决于树木的大小。示踪剂以 1 至 18 m d−1 的速度行进，注射后 1 至 12 天之间，研究树树冠的氘浓度达到最大。示踪剂停留时间约为 5 至 22 天，没有证据表明较大树木的停留时间更长。也没有证据表明示踪剂速度与计算出的木质部比电导率之间存在关系，不同物种之间的木质部比电导率相差近一个数量级。然而，水输送的土壤到叶子的驱动力可能是跨物种示踪速度的重要决定因素，并且在水文建模应用中显示出作为液流速度代理的前景。版权所有 © 2016 约翰·威利父子有限公司
Trees are responsible for the majority of precipitation recycling over land and can affect soil water storage, stream flow, and ground water recharge. Historically, water has not often been limiting in eastern U.S. forests. As a result, little work has been done to understand the timing of water use by vegetation in these systems. We used deuterium tracer, sap flux, and anatomical techniques to study tree water transport on a forested ridge top in central Pennsylvania. Three trees of each of the dominant ring‐porous species,Carya tomentosa(mockernut hickory),Quercus prinus(chestnut oak), andQuercus rubra(red oak), and the diffuse‐porousAcer saccharum(sugar maple), were studied. We hypothesized that tracer velocity would be higher in the ring‐porous species because of their greater vessel diameters and water transport efficiency, but that tracer residence time would be largely dependent on tree size. The tracer travelled at velocities of 1 to 18 m d−1with maximum deuterium concentration in the crowns of the study trees being reached between 1 and 12 days after injection. Tracer residence time ranged from about 5 to 22 days with no evidence of longer residence times in larger trees. There was also no evidence of a relationship between tracer velocity and calculated xylem specific conductivity, which varied by nearly an order of magnitude between species. However, the soil‐to‐leaf driving force for water transport may be a strong determinant of tracer velocity across species, and shows promise as a proxy for sap velocity in hydrologic modelling applications. Copyright © 2016 John Wiley & Sons, Ltd.