Abstract
We examined the way of estimating the thinning effect using eye measurement in conventional qualitative thinning and line thinning to utilize the high-performance and cost-effective yarding machine. Trees that have no thinning effects in qualitative thinning were occupied by 5.5% less than 12.8% in line thinning. So, it found that the effect like a qualitative thinning was gotten by cutting additional few trees. Growth rate of basal area during the 5-year period had increased 8.5%〜13.2% in proportion to open space around canopy.
