Plant architecture characteristics of Corylus mandshurica in Shanxi

Corylus mandshurica was selected for study in the Dahe forest area in the Zhongtiao mountains, Mianshan, Xingtangsi, and Qiliyu forest areas in the Taiyue mountains, Jingangku forest area in the Wutai mountains, and Wangzhuangbao forest area in Hengshan of the Shanxi Province. Using six quadrats, the configuration and fractal dimension characteristics of C. mandshurica in different habitats were studied. Results showed that the overall bifurcation ratio and the ratio of branch diameter (RBD_2:1, RBD_3:2) in the Dahe forest area were higher than those in other areas. The stepwise bifurcation ratio exhibited the opposite trend as the overall bifurcation ratio, and the stepwise bifurcation ratio of C. mandshurica in the Wutai mountains was the highest. However, the branch angle of C. mandshurica showed significant differences in each studied area. The branch angle gradually decreased from the first-class to the third-class in the northern territories. The first-class branch angle of C. mandshurica in the Jingangku forest area was the highest. The order of C. mandshurica branch length was Jingangku > Wangzhuangbao > Qiliyu > Xingtangsi > Mianshan > Dahe, which exhibited a weakening trend from the first-class to the third-class. Fractal dimension was an important indicator, and clarified the complexity of plants. The greater the fractal dimension value, the stronger the plant occupied the space and the greater the potential use of space resources. The crown fractal dimension and bifurcation dimension of C. mandshurica were the highest in Jingangku. The crown structure was closely related to biomass. Leaf area, leaf biomass, and branch biomass from the side reflected the architectural characteristics of the plants. We analyzed the relationship among plant architecture, leaf area, and aboveground biomass. Leaf area and aboveground biomass of C. mandshurica gradually decreased from north to south of Shanxi Province. The average leaf area, leaf biomass, and branch biomass of C. mandshurica were the greatest in Jingangku. Results showed that the growth of C. mandshurica was the best in Jingangku compared with the other study areas, thus reflecting the area in which climate conditions were optimum for C. mandshurica.