STRUCTURE AND YIELD OF ALL-SIZED AND EVEN-SIZED SCOTS PINE-DOMINATED STANDS

This study is based on material collected in southwestern Finland using a systematic temporary circular plot line survey method. A total of 273 sample plots were included in the study. These plots represented Scots pine (Pinus sylvestris L)-dominated stands established on dryish mineral soil sites. In half of the sample plots the stand structure was all-sized (ie stem distribution resembled an inverted letter J). Even-sized stand structure (stem distribution resembled a normal distribution) applied in the case of 31% of sample plots while 17% were irregularly uneven-sized in structure. The number of trees per hectare in the all-sized stands was more than twice that of even-sized stands. The mean annual increment increased along with an increase in growing stock volume. The volume in even-sized stands was higher than in all-sized stands but their mean annual increment was equal. Nevertheless, in stands with equal average volume (125 +/- 25 m3/ha), the mean annual increment in all-sized stands was one third higher than in even-sized stands.