Factors of Water-Use Efficiency Represented by Leaf Carbon-13/Carbon-12 Isotope Ratios among Pine and Fir Species in the Lake Tahoe Basin
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Description
Abiotic factors change along elevation gradients and influence biotic factors such as vegetation water use and photosynthetic demands. In this study, we collected needle samples from White Fir, Sugar Pine, and Jeffrey Pine at six sites around the Lake Tahoe Basin (LTB). We measured the needle carbon-13/carbon-12 isotope ratios (Delta 13C) processed independently of our lab as an index for plant water use efficiency. The six sites differ slightly in elevation changes, annual average precipitation, and yearly temperature max and mins. The elevations range from 1921-2149 ft. For the three species we found a trend of the highest negative isotopic values at mid elevations (2012-2078 ft). Jeffrey Pine shows the lowest isotopic values overall, being most water-use efficient on average. White Fir shows the highest isotopic values overall, although only slightly higher than Sugar Pine. The findings of this study contribute to knowledge of LTB native species' water-use efficiency and predictability of responses to drought stress.
Factors of Water-Use Efficiency Represented by Leaf Carbon-13/Carbon-12 Isotope Ratios among Pine and Fir Species in the Lake Tahoe Basin
Abiotic factors change along elevation gradients and influence biotic factors such as vegetation water use and photosynthetic demands. In this study, we collected needle samples from White Fir, Sugar Pine, and Jeffrey Pine at six sites around the Lake Tahoe Basin (LTB). We measured the needle carbon-13/carbon-12 isotope ratios (Delta 13C) processed independently of our lab as an index for plant water use efficiency. The six sites differ slightly in elevation changes, annual average precipitation, and yearly temperature max and mins. The elevations range from 1921-2149 ft. For the three species we found a trend of the highest negative isotopic values at mid elevations (2012-2078 ft). Jeffrey Pine shows the lowest isotopic values overall, being most water-use efficient on average. White Fir shows the highest isotopic values overall, although only slightly higher than Sugar Pine. The findings of this study contribute to knowledge of LTB native species' water-use efficiency and predictability of responses to drought stress.