Similar potential of foliar δC and silicon levels for inferring local climate information in the Tibetan Plateau region.

Stable carbon isotope ratios (δC) are widely used as climate proxies for assessing and predicting climatic information at an annual resolution. However, the detailed information in the isotopes that results from intra-annual climate scenarios and is associated with mineral accumulation remains unclear. Combined with investigations of elements and ash contents, variations in foliar δC in relation to annual, winter and summer climate scenarios were investigated in a dendroclimatologically important tree species Sabina przewalskii Kom. Foliar δC exhibited a significant negative correlation with mean annual temperature, mean annual precipitation and mean annual relative humidity as well as significant positive correlations with elevation. Climatic factors in winter and summer have opposite effects on the variation of δC. The beneficial mineral element Si had a significant positive correlation with foliar δC, whereas the essential mineral elements K, Ca, and Mg did not. Specifically, Si and δC have similar correlations with climate factors and elevation. These results suggest that measurement of Si content has a similar potential to δC for use as an alternative climate indicator when detailed climatic information may otherwise be limited and provide a basis for understanding the integration of δC in plant responses to climate.