Study On Tree Architecture Of Pinus Sylvestris L. Var. Mongolica Plantation

Based on data of the stem analysis, branch analysis and biomass from 60 sample trees of 12 permanent plots for Mongolian pine (Pinus sylvestris L. var. mongolica) plantation with different age and different stand density, crown architecture characteristics, model of crown factors which affect crown architecture and fractal dimension of crown were discussed. The results indicate that:(1) Bifurcation ratio is positively related with the tree size and it is negatively related with the stand density. For the suppressed trees in stand, the bifurcation ratio does more affect from the stand density. (2) The mean branching number of primary and secondary branches are 3.84 and 2.80, respectively, and both of the branching probability follow normal distribution. The primary branches for different sizes show the average number of branches in each whorl is similar between dominant and suppressed trees, and they are larger than middle trees. The average number of primary branches in each whorl for the trees growing in higher stand density is fewer than lower stand density. (3) The distribution of branching angle follows normal distribution, and mainly distribute from 30° to 60°. The branching probability of primary branches with larger branching angle increases with relative depth into crown increasing. The probability distribution of branching angle is similar between dominant and suppressed trees. The branching angle for the trees within higher stand density are smaller, and mainly distribute from 0° to 40°. (4) Branching pattern of the primary branches around the bole follows rectangle distribution, and it is not affected by tree size and stand density. (5) vertical distribution about stem biomass is followed a line, and slope increases with the tree size increasing Vertical distribution of foliage biomass is followed one peak form. Biomass decreases with the stand density increasing in the same relative depth into crown (6) Using the independent test data sets ,the validation results of predicting models for crown variables showed that the branch diameter, branch length, and branch chord length model were suitable for describing the changing of architecture factors in different stands. (7) The crown fractal dimension is between 2.4 and 2.8. With the age increasing, the crown fractal dimension increased gradually. The complex level of crown structure and the ability of occupying growth space also increased.By studying on crown architecture of Mongolian pine plantation, the ability of occupying growth space, growth resources, and adaptive principle were understood. These results will provide the scientific foundation for explaining and evaluating management methods which affected on tree or stand growth.