Patterns of invasion by Quercus glauca in a coppice forest of pine and deciduous oaks as a function of topography at a hilly site in Toyota City, Aichi Prefecture, Japan

Abstract

The process of succession from a secondary coppice forest of pine and deciduous oaks to an evergreen broadleaved oak forest was investigated on a hilly site in Toyota City, Aichi Prefecture, Japan. A 100×150m plot was established in the secondary forest, and the plot was divided into 150 quadrats categorized for three topographic positions: ridge, slope, and valley. The distribution, height and age of evergreen Quercus glauca individuals were measured in each quadrat. Further, the measurment of the growth of leader shoots was conducted and dead individuals were checked from June 1999 to April 2001. There occurred numerous Q. glauca saplings in the study plot, being 683/ha in density. The height of all individuals except one was less than 5.0m, showing the maximum age of about 40. The density of Quercus saplings was lower (3.3/100m^2) on the ridge, but higher on the slope and in the valley (8.5/100m^2 and 10.3/100m^2, respectively). This low density on the ridge is correspondent with the high mortality of the saplings on the ridge compared with higher density and lower mortality of those saplings on the slope and in the valley. The height growth per year was the largest in the valley. Based on our findings, we predict that the coppice forest will be replaced by Q. glauca faster in the valley than on the slope and the replacement will likely be retarded for longer on the ridge.