Analysis of release cutting effects on increment and growth in Oriental beech (Fagus orientalis Lipsky) stand

In the present study, the effects of release cuttings on stand structures and increment and growth relations were investigated in afforested oriental beech (Fagus orientalis Lipsky) stands. To maximize spatial variation in dataset, stratified random sampling was used to layout transects. 24 sampling plots were determined which reflects average characteristics of actual stand structure. 8 sampling plots were selected from unthinned stands, 8 sampling plots were selected from lightly thinned (19% of the total basal area removed) stand and 8 sampling plots were selected from heavily thinned (40% of the total basal area removed) stand. Light thinning was done in the year 2008 and heavy thinning in 2009. Stem analyses were carried out and pre- and post-treatment height, diameter, basal area and volume increments were examined according to thinning intensities. Obtained results showed that removal of 40% of the basal area does not contribute to stand increment and growth more positively than those in stands treated by removal of 19% of the basal area. Expected increase in height and diameter increment did not occurr post-treatment in 2008 and 2009. However, in only lightly thinned stands mean basal area increment increased after treatment. Release cuttings in beech stand needs to be practiced at least twice every 5 to 6 years, provided that peculiar characteristics of every habitat are considered.