DELTA-C-13 RECORDS OF JAPANESE CEDARS FROM YAKUSHIMA ISLAND AND PAST ATMOSPHERIC CO2

delta(13)C records of annual growth rings of two Japanese cedars (Cryptomeria japonica) from Yakushima Island, southern Japan are presented for the past 200 years. Some portions of the shortterm fluctuations in the delta(13)C records from the Japanese cedars are correlated with the variabilities of the ring-thickness index. Regressions between the ring-thickness indices and delta(13)C values were used to ''correct'' the delta(13)C records for local climate and environmental effects. These corrected delta(13)C records from the two Japanese cedars show a steady downward trend with time, but with pronounced short-term fluctuations superimposed on the trend. The overall delta(13)C fall from 1870 to the present is between 1.2-1.4 parts per thousand, consistent with the delta(13)C records of atmospheric CO2 estimated from ice-core bubbles, which show a fall of 1.14 +/- 0.15 parts per thousand from 1740 to the present (Friedli et al., 1986). The delta(13)C fall seems to be related to the increase in the concentration of atmospheric CO2 as a result of fossil fuel burning and deforestation. The corrected delta(13)C records show small increases at 1900 and 1950, which can not be explained satisfactorily at present.