EVALUATION OF THE EFFECTS OF CLIMATIC AND NONCLIMATIC FACTORS ON THE RADIAL GROWTH OF YEZO SPRUCE (PICEA-JEZOENSIS CARR) BY DENDROCHRONOLOGICAL METHODS

The responses to climatic and nonclimatic factors of Yezo spruce (Pice a jezoensis Carr) trees growing in a natural forest in Tomakomai, Hokk aido were analyzed by dendrochronological methods. The effects of clim atic factors were examined by response function analysis. More than 70 % of the variance of ring-width and maximum-density indices was expla ined by climatic data from 1924 to 1965. The effect of nonclimatic fac tors on radial growth from 1966 to 1990 was analyzed by comparing actu al indices with the estimated indices of ring width and maximum densit y calculated from the climatic data. Actual ring-width indices were lo wer than the estimated indices every year from 1969 to 1977. Actual ma ximum-density indices were lower than the estimated indices every year from 1971 to 1974. These results indicate that some nonclimatic facto rs might have affected both ring width and maximum density in the 1970 s. ((C) Inra/Elsevier, Paris.).