Effects of Climate Factors on the Tree-ring Structure of Cryptomeria japonica in Central Japan

We investigated the effects of climate factors on tree-ring structure of (cid:9479)(cid:9526)(cid:9533)(cid:9524)(cid:9528)(cid:9523)(cid:9521)(cid:9513)(cid:9526)(cid:9517)(cid:9509)(cid:9444)(cid:9518)(cid:9509)(cid:9524)(cid:9523)(cid:9522)(cid:9517)(cid:9511)(cid:9509) in central Japan. We collected cores from 33 plantation trees in the Takayama evergreen coniferous forest site at Gifu University and measured annual ring width （RW）, annual mean density （RD）, earlywood width （EW）, latewood width （LW）, earlywood density （ED） and latewood density （LD） by X-ray densitometry. We also calculated annual ring weight growth （RWG） by multiplying RW and RD. We developed seven residual chronologies of the parameters of tree-ring structure by a dendroecological method. Pearsonʼs correlation analysis was applied to assess relationships among the chronologies, and relationships between the chronologies and climatic factors. EW showed significant positive correlations with RW and RWG. Moreover, EW showed significant positive correlation with the temperature current from March to April. These results indicate that EW is the most dominant factor which regulates RW and RWG of (cid:9479)(cid:9458)(cid:9444)(cid:9518)(cid:9509)(cid:9524)(cid:9523)(cid:9522)(cid:9517)(cid:9511)(cid:9509)(cid:9458) It is suggested that EW increases by the temperature rise of early spring before reactivation of cambium activity, and subsequently RW and RWG will increase.