Abstract
The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the snowmelt and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between snowmelt and leaf-out, taking up 21-25% of the available snowmelt water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8-20.9 billion m3 of snowmelt water, which is equivalent to 8.7-10.2% of the Yukon River's annual discharge. Deciduous trees transpired 2-12% (0.4-2.2 billion m3) of the absorbed snowmelt water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10-30% (2.0-5.2 billion m3) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1-15%, potentially resulting in an additional 0.3-3 billion m3 of snowmelt water removed from the soil per year. This study is the first to show that deciduous tree water uptake of snowmelt water represents a large but overlooked aspect of the water balance in boreal watersheds.
| Original language | English |
|---|---|
| Article number | 29504 |
| Journal | Scientific Reports |
| Volume | 6 |
| DOIs | |
| State | Published - Jul 12 2016 |
Funding
This work was part of the U.S. Geological Survey (USGS) Changing Arctic Ecosystem Initiative and was supported by the Wildlife Program of the USGS Ecosystem Mission Area. We thank NSF Hydrology grant #1114457 and the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Scientific Discovery through Advanced Computing (SciDAC) program grant #DE-SC0006913 for funding J. Young-Robertson and W.R. Bolton. U. Bhatt received financial support from the Alaska Climate Science Center, funded by Cooperative Agreement G10AC00588 from the United States Geological Survey. Any use of trade names or products is for descriptive purposes only and does not imply endorsement by the U.S. Government. We thank R. Busey, W. Cable, S. Dempster, S. Straus, C. Glover, M. Plumb, and L. Barron for field assistance.