Growth Characteristics of <i>Quercus serrata</i> and <i>Quercus glauca</i> Seedlings in a Restored Urban Forest After Approximately 20 Years Since Construction

Abstract

To clarify the regeneration processes of two Quercus (Fagaceae) species, Quercus serrata, deciduous broad-leaved tree and Quercus glauca, evergreen broad-leaved tree in an urban forest, 163 research quadrats (163 m2) on the forest floor in a restored deciduous broad-leaved forest, "Inochi- No-Mori" in Kyoto city after approximately 20 years since construction were set up. Growth characteristics, recruitment, mortality and relative height growth rates of seedlings of these two species were investigated. As a result, the recruitment rate of Q. serrata seedlings tends to be higher than that of Q. glauca seedlings, when diffuse site factor was larger than 15.0%, particularly. The relative height growth rate of Q. serrata seedlings in the 15–50-cm height class was relatively high when diffuse site factor was larger than 15.0%. On the other hand, the mortality rate of Q. glauca seedlings in the 15–50-cm height class was very lower than that of Q. serrata seedlings. These results indicate that in order to promote the regeneration of Q. serrata in this site, it is necessary to maintain a light environment with a diffuse site factor amount of larger than 15.0% around the mature Q. serrata trees, by thinning the upper trees and to selectively remove Q. glauca seedlings.