Abstract: This paper determined the δ¹³C annual series of three Cryptomeria fortunei tree rings at West Tianmu Mountain,and analyzed their similarities and differences.In the period of 1837～1982,the correlations among the three δ¹³C series were significant,with r₁₂=0.47,r₁₃=0.65 and r₂₃=0.52 (P<0.001,n=146),respectively.After removing the high-frequencies from the original δ¹³C series by using polynomial function model,a significant correlation was observed among three low-frequencies,with the correlation coefficient varied from 0.95 to 0.998.A significant correlation was also observed between original low-frequencies and simulated high-frequencies,with the correlation coefficient being 0.79～0.84.The three δ¹³C annual series had similar high-frequency and low-frequency variations.High-frequency variation recorded similar climate variation information,while low-frequency reflected the information of atmospheric CO₂ changes.It was the common case for different individuals of trees that in the three δ¹³C annual series,climatic factors caused highfrequency change,while atmospheric CO₂ concentration caused low-frequency variation.The differences among the three δ¹³C annual series were mainly caused by the local environmental conditions at the growth sites of trees,while the individual difference among the three δ¹³C series caused by local environmental conditions had very small effects on the changes of the three δ¹³C series.It could be concluded that the differences among the three δ¹³C series did not affect the suitability of using tree ring’s δ¹³C annual series as the indirect evidence in climatic variation study,and the reliability and coherence of reconstructing historical climate changes.

Key words: Soil, Mineral nutrient, Quality of agricultural products, Human and livestock health