CLIMATIC IMPLICATIONS OF DELTA-C-13 VARIATIONS IN A JAPANESE CEDAR (CRYPTOMERIA-JAPONICA) DURING THE LAST 2 MILLENIA

Tree-ring delta(13)C of both modern Japanese cedars, and of a giant Japanese cedar growing throughout the last two millennia on Yakushima Island, southern Japan, were studied. delta(13)C of eleven modern trees from 320 m to 1700 m above mean sea level revealed a strong dependency on tree growth-elevation and a decreasing trend from the late 19th century to the present. Changes in both climate and delta(13)C of atmospheric CO2 appear to be important for these changes. Assuming temperature change to be a dominant factor influencing delta(13)C-growth elevation relationship, we have inferred a temperature dependency of delta(13)C, -0.29 +/- 0.02 parts per thousand degrees C-1 for Japanese cedar. Applying this relationship to a decadal-delta(13)C time series of a giant Japanese cedar, we reconstructed a high-resolution climatic record for the last two millennia. A maximum-entropy spectral analysis of the tree-ring delta(13)C time series revealed a resemblance of that of other climatic proxy, and the presence of the well-known periodicity (ca 90 and near 200 years), characteristic of tree-ring Delta(14)C, governed by solar modulation of galactic cosmic rays. Supporting evidence for a Sun-climate relationship was presented.