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DOI	10.5194/hess-23-1199-2019
	Seasonal origins of soil water used by trees
	Allen S.T.; Kirchner J.W.; Braun S.; Siegwolf R.T.W.; Goldsmith G.R.
发表日期	2019
ISSN	1027-5606
起始页码	1199
结束页码	1210
卷号	23 期号:2
英文摘要	Rain recharges soil water storages and either percolates downward into aquifers and streams or is returned to the atmosphere through evapotranspiration. Although it is commonly assumed that summer rainfall recharges plant-available water during the growing season, the seasonal origins of water used by plants have not been systematically explored. We characterize the seasonal origins of waters in soils and trees by comparing their midsummer isotopic signatures (δ2H) to seasonal isotopic cycles in precipitation, using a new seasonal origin index. Across 182 Swiss forest sites, xylem water isotopic signatures show that summer rain was not the predominant water source for midsummer transpiration in any of the three sampled tree species. Beech and oak mostly used winter precipitation, whereas spruce used water of more diverse seasonal origins. Even in the same plots, beech consistently used more winter precipitation than spruce, demonstrating consistent niche partitioning in the rhizosphere. All three species' xylem water isotopes indicate that trees used more winter precipitation in drier regions, potentially mitigating their vulnerability to summer droughts. The widespread occurrence of winter isotopic signatures in midsummer xylem implies that growing-season rainfall may have minimally recharged the soil water storages that supply tree growth, even across diverse humid climates (690-2068 mm annual precipitation). These results challenge common assumptions concerning how water flows through soils and is accessed by trees. Beyond these ecological and hydrological implications, our findings also imply that stable isotopes of δ18O and δ2H in plant tissues, which are often used in climate reconstructions, may not reflect water from growing-season climates. © Author(s) 2019.
语种	英语
scopus关键词	Aquifers; Cultivation; Evapotranspiration; Hydrogeology; Isotopes; Rain; Soil moisture; Water supply; Annual precipitation; Available water; Climate reconstruction; Isotopic signatures; Soil water storage; Stable isotopes; Summer droughts; Winter precipitation; Forestry; deciduous forest; evapotranspiration; evergreen forest; growing season; humid environment; niche partitioning; percolation; precipitation (climatology); rainfall; recharge; rhizosphere; seasonal variation; soil water; summer; water availability; water flux; water storage; Switzerland; Fagus; Picea
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159743
作者单位	Allen, S.T., Department of Environmental Systems Science, ETH Zurich, Zurich, 8092, Switzerland, Ecosystem Fluxes Group, Laboratory for Atmospheric Chemistry, Paul Scherrer Institute, Villigen, 5232, Switzerland; Kirchner, J.W., Department of Environmental Systems Science, ETH Zurich, Zurich, 8092, Switzerland, Swiss Federal Research Institute WSL, Birmensdorf, 8903, Switzerland, Department of Earth and Planetary Science, University of California, Berkeley, CA, United States; Braun, S., Institute for Applied Plant Biology, Witterswil, 4108, Switzerland; Siegwolf, R.T.W., Ecosystem Fluxes Group, Laboratory for Atmospheric Chemistry, Paul Scherrer Institute, Villigen, 5232, Switzerland, Swiss Federal Research Institute WSL, Birmensdorf, 8903, Switzerland; Goldsmith, G.R., Ecosystem Fluxes Group, Laboratory for Atmospheric Chemistry, Paul Scherrer Institute, Villigen, 5232, Switzerland, Schmid College of Science and Technology, Chapman University, Orange, CA 92866, United States
推荐引用方式 GB/T 7714	Allen S.T.,Kirchner J.W.,Braun S.,et al. Seasonal origins of soil water used by trees[J],2019,23(2).
APA	Allen S.T.,Kirchner J.W.,Braun S.,Siegwolf R.T.W.,&Goldsmith G.R..(2019).Seasonal origins of soil water used by trees.Hydrology and Earth System Sciences,23(2).
MLA	Allen S.T.,et al."Seasonal origins of soil water used by trees".Hydrology and Earth System Sciences 23.2(2019).