Species composition and altitudinal distribution of Quercus serrata secondary forests and Fagus crenata secondary forests in northern Hyogo Prefecture, Japan

Abstract

Changes in species composition of secondary summer-green forests along altitudinal gradient (40- 500 m) were examined in northern Hyogo Prefecture, Japan. Thirty-five forest stands were investigated. The species composition of the stands was analyzed using the phytosociological tabulation method. The results showed that the stands were divided into two types (A and B). Major dominant trees of type A and type B were Quercus serrata and Fagus crenata, respectively. The first-axis score of the detrended correspondence analysis ordination for the stands was highly correlated with values of the warmth index (WI) and the coldness index (CI), suggesting that the differences in species composition between the two stand types were primarily caused by air temperature conditions. Type A stands tended to be replaced by type B stands at approximately 300 m in altitude. This altitude was similar to the altitude at which natural evergreen broad-leaved forests were replaced by natural summer-green forests. The values of WI and CI at an altitude of 300 m were estimated to be 95 ℃ . month and -10 ℃ . month, respectively.