This study was conducted to provide tending operation information for the effective management in unmanaged artificial forests of Pinus densiflora for. erecta, Pinus rigida, and larix leptolepis, based on the study of the comparison of tree growth pattern by residual stand density after thinning practices. Followings are summarized results of this study. 1. The diameter growth of residual trees was increased as residual stand density decreased by thinning practices in the stands of Pinus densiflora for. erecta, and Pinus rigida, and subcompartment (Ga) and (Na) of Larix leptolepis. The statistical analysis noted that the tree growth was significantly different by the residual stand density. 2. The height growth did not show corresponding results by stand density treatment pattern, which indicated that the height growth was not directly influenced by residual stand density, but by site quality of the stand. 3. The diameter increment for the last six years was proportionately increased in larger diameter classes and less dense stands.