Tracing changes in uptake of precipitation and groundwater and associated consequences for physiology of Douglas-fir and lodgepole pine trees in montane forests of SW Alberta

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Andrews, Shilo F.
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2009
Douglas-fir (Pseudotsuga menziesii) and lodgepole pine (Pinus contorta) in southwestern Alberta were studied to determine the water sources used and the effect of changing soil moisture on tree ecophysiological function. The hydrogen stable isotope ratios of water from local groundwater and precipitation were compared to tree stem water to determine the amount of stem water coming from those two sources. There were no significant differences between species in the portion of summer precipitation taken up. However, Douglas-fir shifted towards using more groundwater as shallow soil moisture declined. In addition, Douglas-fir showed large changes in shoot water potential, but maintained relatively constant rates of oxygen evolution, whereas lodgepole pine exhibited smaller changes in shoot water potential and had severely reduced rates of oxygen evolution during mid-summer drought. Lower leaf-area to sap-wood area and higher leaf δ13C (carbon isotope composition) suggested a less efficient hydraulic system in Douglas-fir compared to lodgepole pine.
x, 91 leaves : ill. ; 29 cm
Douglas fir -- Climatic factors -- Alberta, Southwest , Douglas fir -- Effect of soil moisture on -- Alberta, Southwest , Lodgepole pine -- Climatic factors -- Alberta, Southwest , Lodgepole pine -- Effect of soil moisture on -- Alberta, Southwest , Climatic changes -- Research -- Alberta, Southwest , Upland ecology -- Alberta, Southwest , Dissertations, Academic