Effect of spacing on growth and quality parameters in sessile oak (Quercus petraea) stands in central Poland: results 7 years after planting

We examined the growth and quality of young oaks in stands established at three different spacings. The three densities were the traditional level, that is, 8000 seedlings ha−1 (1.5 × 0.85 m) plus two where the initial density was decreased by 50% and 70%, achieved by increasing the distance between the rows from 1.5 to 3 or 4.5 m. The experiment was located in central Poland on a moderately fertile site. In the two wider spacings, the intention was to use natural regeneration occurring between oak rows as a replacement of intraspecific competition for oaks. The mean height was only affected in the third and the fourth year after establishment. Subsequently, the differences between spacings with respect to both growth and quality traits were insignificant and small. At lower densities, natural regeneration of willow and aspen was abundant and inter-species competition replaced intra-species competition, thus explaining the absence of a spacing effect on growth and quality properties. In the study period, ...