Patterns and factors in early-stage vegetation recovery at abandoned plantation clearcut sites in Oita, Japan: possible indicators for evaluating vegetation status

Abstract

The abandonment of sites after clearcutting plantations is increasing rapidly in Japan. Although a few stand-level studies have been conducted, a broad-scale study is needed to understand the general tendency of vegetation recovery and to obtain information for the management of such extensively distributed abandoned clearcut sites. This study is a province-level study that aims to interpret the patterns and factors in early-stage vegetation recovery at abandoned plantation clearcut sites. We also discuss the potential indicators that may determine whether a certain site recovers towards evergreen broad-leaved forest consisting of Castanopsis cuspidata and Quercus glauca or towards deciduous broad-leaved forest comprising Q. serrata and Q. acutissima. A cluster analysis revealed that five types of vegetation (evergreen trees, evergreen trees–deciduous pioneer shrubs, pioneer species, deciduous trees, and deciduous shrubs) were observed from an early stage of succession. The first two vegetation types were considered to recover successfully to the target vegetation of evergreen broad-leaved forest, but the remaining three vegetation types did not show any tendency to recover to the target vegetations. According to the results of the detrended correspondence analysis, a smaller size of the abandoned site with adjacent evergreen broad-leaved forest and a longer time after clearcutting were identified as factors that enhance the invasion of evergreen tree species; these factors are also useful to predict the future successional tendency. In conjunction with these factors, the existence of regeneration sources (i.e., stumps) that allow sprouting appeared to be an important indicator for predicting the early-stage vegetation recovery.

Keywords:

• Clear cutting
• Environmental conditions
• Regeneration sources
• Secondary succession
• Target vegetation

Acknowledgments

We would like to express our appreciation to Oita Prefecture for providing the data of the survey on abandoned sites that was conducted in 1998. In addition, we would like to thank Ms. Yumiko Imamura for digitizing the distribution map of the abandoned sites in Oita Prefecture. This study was conducted as a part of the Research Project for Utilizing Advanced Technologies in Agriculture, Forestry and Fisheries from the AFFRC of Japan (no. 1614) and Grant-in-Aid for JSPS Fellows (no.198314).