Growth of Young Stands of Silver Birch (Befula pendula Roth.) Depending on Pre-Commerdai Thinning Intensity

摘要

First pre-commercial thinnings at the average stand height of 3-6 m, leaving 1,500 - 2,000 trees ha1 regardless of the stand density before thinning, are among the major tending practices in order to create highly productive stands. After the stand has reached the average height of 10 m, thinning from below has, for at least 12 years after thinning, no significant effect on the remaining stand. It is likely that self-pruning is a genetical particularity and has no bearing on the thinning intensity. The field data of 26 sample plots of the experiment on young birch stands thinned with varying intensities show the taper ratio to be of no significance for reducing the risk of snow damage. The assumption that the HD1 ratio in stable stands should be below 1.0 is not confirmed.