AUTHOR=Liu Xinsheng , Nie Yuqin , Luo Tianxiang , Yu Jiehui , Shen Wei , Zhang Lin TITLE=Seasonal Shift in Climatic Limiting Factors on Tree Transpiration: Evidence from Sap Flow Observations at Alpine Treelines in Southeast Tibet JOURNAL=Frontiers in Plant Science VOLUME=7 YEAR=2016 URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.01018 DOI=10.3389/fpls.2016.01018 ISSN=1664-462X ABSTRACT=
Alpine and northern treelines are primarily controlled by low temperatures. However, little is known about the impact of low soil temperature on tree transpiration at treelines. We aim to test the hypothesis that in cold-limited forests, the main limiting factors for tree transpiration switch from low soil temperature before summer solstice to atmospheric evaporative demand after summer solstice, which generally results in low transpiration in the early growing season. Sap flow, meteorological factors and predawn needle water potential were continuously monitored throughout one growing season across Smith fir (