Abstract: Based on the branch analysis data from 30 sample trees of 6 permanent plots for Mongolian pine (Pinus sylvestris var. mongolica) plantation, the branching structure of crown was discussed by analyzing the branching probability, branching pattern, branching angles of primary and secondary branches for different stand conditions and tree sizes in Mongolian pine plantation. The mean branching number of primary and secondary branches was 3.84 and 2.80, respectively, and both of the branching probability was followed the normal distribution. The distribution of around the bole for primary and secondary branches was mainly distributed in the range of azimuth (from 46°~225°) where had a good light condition. An uniform was appropriate to reflect branching pattern around the bole for primary branches, not for secondary branches. The branching angle at the upper part of crown was smaller than the middle and lower part of crown, and mean branching angle in the upper crown and the middle or lower crown was 45.6°and 49.4°, respectively. The branching structure of primary branches for different sizes showed the average number of branches in each whorl was similar between dominant and suppressed trees, 3.89 and 3.94, respectively, and they were larger about 0.5 than middle trees. The differences of horizontal distribution for primary branches in each azimuth intervals (45° class size) were 0.24%~2.81% and they were not significant from ANOVA for different tree sizes. The mean branching angles for dominant, middle, and suppressed trees were 48.5°、42.2°、50.7°, respectively.

Key words: Pinus sylvestris var. mongolica, branching probability, branching pattern, branching angle