Tree trunks reveal climate change impact with decreasing carbon isotope ratios.
The carbon isotope ratios in Sabina przewalskii vary in different parts of the tree. Leaves have the lowest ratio, while trunks have the highest. The ratio also changes with the tree's exposure, being lowest in the north. Wood at different heights along the trunk shows inconsistent ratios, suggesting no discrimination during the transport of organic compounds. Over the past 60 years, wood ratios have been decreasing regardless of tree height or exposure.