Abstract
Field survey was conducted to examine trees and soils in the forested area of the Expo' 70 Commemorative Park for 30 years after reclamation. Twelve sample sites were selected in the forest where the previous studies were conducted. In each site, all trees (DBH>=1cm) were surveyed and soils at 0-5, 20-25, 50-55cm depth were sampled for investigating physical and chemical properties. The canopies reached over 10m and most of canopy species were evergreen broad-leaved trees. Declination of tree density did not occur in comparison with increase of average tree volume and the density was kept high. Regeneration of the canopy dominant species did not successfully occur. The soil physical properties were improved in the most plots, especially at deep soils (20-25 and 50-55cm), to the level of no unwilling influence for the growth of tree root system. Although physical properties of Osaka group soil were bad in the past study, yield per hectare was maximum at the plot on Osaka group soil, where trenches were dug for drainage after the monitoring in 1982. It was suggested that appropriate management can lead to satisfactory forest development even on the site dominated by Osaka group soil.
