Evidence of century-scale environmental changes: Trace element in tree-ring from Fuling Mausoleum Shenyang, China

Abstract

In order to detect the response of trees to environmental pollution in Shenyang during the last century, tree rings of two 100+ year old Chinese pine (Pinus tabulaeformis Carr.) were analyzed for nine trace element concentrations (K, Ca, Mg, Mn, Cu, Zn, Al, Pb and Cd) and compared to local environmental change. The concentrations of Cu, Zn and Al had significant (p<0.01) increasing trends after 1940s and correlated significantly (p<0.01), with increasing production of nonferrous metal from local industrial processing. Concentrations of nutrient element (K, Ca and Mg) showed significant (p<0.01) increasing trend from heartwood to sapwood with declines in the last three decades. Significant correlation between climatic factors and element concentration in tree rings were also found, in which the temperature (November to May) and relative humidity in April and May showed significant positive correlation with Ca, Zn and Cu (p<0.05) as well as Al (p<0.01) concentrations in tree rings. April rainfall showed significant positive correlation with K and Zn (p<0.05) as well as Al (p<0.01) concentration in tree rings. The results suggest that tree rings from Chinese pine in Shenyang are sensitive to environmental change and have the potential to be used as a biomonitor for the environmental pollution. The results also demonstrate the feasibility of applying dendrochemical techniques to areas with limited samples.