Evaluation of Spatial Structure of Picea schrenkiana Forest and its Effect on Radial Growth of Single Tree

Based on the monitoring data of 8 hm2 permanent sample plots from 2014 to 2024 in Xinjiang Tianshan Forest Ecosystem Observation and Research Station, the spatial structure characteristics (uniform angle index, neighborhood comparison, openness and mingling) of Picea schrenkiana forest in central Tianshan Mountains and their effects on the growth rate of DBH and the increment of basal area were analyzed. The results showed that the angle scale of P.schrenkiana forest was dominated by random distribution and uneven distribution, with frequencies of 0.486 and 0.468, respectively. The size ratio distribution pattern is relatively uniform, the openness is seriously insufficient, the frequency is 0.652, the mingling is extremely low, and the zero mingling accounts for 0.965. The growth rate of diameter at breast height was the highest when the angle scale was 0 (absolutely uniform). The size ratio was negatively correlated with the growth rate of diameter at breast height and the increment of chest height (P<0.01). The growth rate of diameter at breast height was the highest when the size ratio was 0 (dominant state). The mingling degree was significantly positively correlated with the DBH growth rate (P<0.01), and the DBH growth rate was the highest when the intensity was mixed (0.5<M≤0.75). There was a significant positive correlation between openness and DBH growth rate (P<0.01), but it had no significant effect on the increment of basal area of chest height. The DBH growth rate was the highest when the openness was sufficient (K>0.5).