Influence of Past Land-uses on Vegetation Structure in the Sprawled Satoyama Woodlands

Abstract

This study examined the spatial structure of vegetation in the sprawled Satoyama woodlands, which is thought to have been shaped by past land-uses. During the mid-20th century, the upper slopes of the hillside surrounding arable land in the surveyed area were covered with naturally grown forests. Conversely, the lower slopes bordering the arable land were characterized by low vegetation that is thought to be grasses or brushes. According to residents, in the mid-20th century, forests on the upper slopes were harvested for firewood and charcoal production every 10 years or more, whereas grasslands on the lower slopes were managed as meadows and mowed multiple times every year. Differences were observed in the present-day woodland's species composition between sites previously occupied by naturally grown forests and those covered with grasses or shrubs in proximity to arable land. Notably, Quercus serrata, which overwhelmingly dominates the former sites, was entirely absent in the latter. Q. serrata is believed to have maintained natural populations in coppices, grasslands, and brushlands owing to its proficient sprouting and precocious reproduction. However, instances of exceedingly frequent disturbance (occurring multiple times annually) by mowing likely inhibited Q, serrata from sprouting, seed regeneration, and, ultimately, population establishment. Thus, the vegetation in the sprawled Satoyama woodlands had an inhomogeneous spatial structure reflecting the effects of past land use.