Impact of the harvest of logging residues at the thinning on the soil chemical and physical properties, and the stand growth of Japanese cedar (Cryptomeria japonica)

Abstract

To clarify the impact of harvesting logging residues at thinning on the soil properties and stand growth on plots of 45- year-old Japanese cedar (Cryptomeria japonica), we investigated the tree census and carried out a soil survey three years after thinning at whole-tree harvesting, short wood logging, and no harvesting (no thinning) plots in Kamaishi, Iwate Prefecture, Japan. The results for the chemical and physical soil analysis showed low porosity in the whole-tree harvesting plot, while no significant differences were found in the chemical properties of the soil among the plots. The low percentage of vegetation cover by the forest floor vegetation in the whole-tree harvesting plot resulted in heavy soil movement and caused the reduction in soil porosity. The impact of harvesting logging residues on the stand growth was inconclusive, although the stand growth at the whole-tree harvesting plot tended to be lower than that at the other plots studied. These results indicate that harvesting logging residues at thinning on steep slopes may influence soil physical properties.