Geographical distribution of Aralia elata characteristics correlated with topography and forest structure in Heilongjiang and Jilin Provinces, Northeast China

The Araliaceae family consists of numerous species of medical plants of significant value as non-wood forest products. To conserve and culture these plants in natural forest stands is an important undertaking which should be implemented according to the relationship between forest structure and understory population. In this study, thirty-five plots were established in natural Aralia elata stands. Taller individual and denser populations were found in the northern and in the eastern regions, respectively. Both population densities and individual leaf weight increased along longitude. In contrast, their relationship with elevation and DBH were negative. Along with the altitude gradient, both height and root-collar diameter increased but population density declined. Root-collar diameter and population density decreased with latitude and DBH, respectively. Overall, dominant trees unlikely enforced strong disturbance to the development of understory A. elata populations unless concerning some specific topographic factors.