Characteristics of Legacy Trees with Hollows in the Urban Area of Kyoto City, Japan

Abstract

Tree hollows are important nest and roost sites for various animals such as Ninox scutulata even in urban areas, but the number of such sites is very low. In this study, we recorded the characteristics of legacy trees with hollows in an urban area within Kyoto City (25 km2), Japan in 2002. We found 288 legacy trees with a trunk perimeter more than 300 cm and 94 trees with hollows. Legacy trees of Castanopsis sieboldii (an ever-green broad-leaf tree) and Aphananthe aspera (a deciduous broad-leaf tree) had a high rate of hollows. All six legacy trees of Cinnamomum camphora (an ever-green broad-leaf tree) with more than 1.5 m of DBH had hollows, but other trees of this species did not have hollows even when the trunk perimeter was more than 300 cm. We applied a logistic regression model to trunk perimeter and the probability of hollow-bearing in each species in an urban woods. We also predicted tree perimeter in relation to age from the annual relative growth rate in each species. A. aspera trees showed the highest incidence of tree hollows in relation to trunk perimeter, but these trees grow very slowly. Celtis sinensis trees grow rapidly, but they have a lower rate of tree hollows than A. aspera. Z. serrata trees grow at an intermediate speed and rarely have tree hollows. Cinnamomum camphora trees grow rapidly. Castanopsis sieboldii trees grow at an intermediate speed.