Periodic annual increment of tree volume by thinning intensity during each growth period in the Korean white pine plantation and oak-dominated natural deciduous forest. Only the trees that survived the entire measurement period were analyzed. The plots were thinned with different intensities at the first measurement period: Plot A with heavy thinning treatment, Plot B with moderate thinning treatment, Plot C with light thinning treatment, and Plot D with unthinned treatment. Specific thinning intensities are provided in Table 2
. Significant differences between thinning treatments at each measurement are indicated by different letters based on Duncan’s multiple range test (alpha = 0.05).