ABSTRACT

δ¹³C fluctuations within a ring and secular δ¹³C changes of a Japanese cedar tree from Mt. Amagi in the Izu Peninsula, central Japan, are presented. δ¹³C values within a ring show a characteristic fluctuation in which the δ¹³C values in the early wood layer are smaller than that in the late wood layer. The mean peak to peak amplitude of the seasonal δ¹³C fluctuation is 1.4 ± 0.3‰, which has not apparently changed with time during the past 120 years. The δ¹³C secular change in annual growth rings shows a downward trend with time, with a δ¹³C rise of about 1‰ between 1940 and 1960. The δ¹³C falls in annual growth rings of Japanese cedar were 0.55‰ from 1860 to 1940 and 1.05‰ from 1960 to 1980, respectively.