Influence of Initial Density of Oak (Quercus robur L.) Plantations on Stem Quality

摘要

Studies were carried out in the 46 year-old oak plantations of different initial density (3,570, 7,140, 12,300 ir 20,000 trees ha~(-1)). It was found that the straightness of oak stems at the height of 0.1 - 5.1 m from the ground surface is distinctlydependant on tree diameter. With increasing tree diameter, stem straightness increases as well. The stems of the thinnest trees are by 2 times more crooked (cm m~(-1)), in comparison with the thickest trees. The straightest stems were in plantations of7,140 trees ha~(-1) initial density. The number of branches and their thickness at 0.1 - 5.1 m height decreases under increasing initial density. Relative distribution of butt logs by quality classes within the range of studied densities is similar, however, with increasing initial density, the number of stems producing butt logs of the highest quality, expressed in percent from the number of planting places, constantly decreases. Second logs, compared with butt logs, most often are of inferior qualityand only in exceptional cases the quality is higher. When butt logs are of the highest quality class, only 15% of second logs remain in the same class. Given the growth of plantations and timber quality, the initial density of oak plantations should be between 3,500-7,140 trees ha~(-1).