A shift of tree species distribution is difficult to assess for adult trees that need long-term observation according to their nature of long life span. However, a shift of establishment area is suggested to be much easier to assess since young trees need less time to establish. Therefore, we analyzed altitudinal shift of canopy tree species in each size class to estimate future distribution.

Present (2009) and past (1962-1984) distribution, from warm temperate to subalpine zone, was compared in canopy (adult) and shrub (young) layer separately. Present distribution was calculated from 50 research plots in Shizuoka Prefecture, and past distribution was calculated using 76 plot data acquired from “Vegetation of Japan”. Every plot was set on ridge, less disturbed site. 15 species that occurred both in present and past dataset were used for analysis.

As a result, young trees shifted to higher altitude though adult trees did not change. Mean altitude rose 105.7 m in young trees and 32.7 m in adult trees, and it was statistically greater than 0 m in young trees (p<0.01) and not in adult trees.

Upward shift of young trees was likely to be caused by abrupt warming event in late 1980s as mean annual temperature had increased for 0.72 °C from 1980s to 1990s. Therefore, in our research, tree species were predicted to move upward.