[Spatial pattern and regeneration characteristics of main woody species in natural secondary forest in Maoershan, Northeast China.]

. For the whole forest, the seedlings in the stand were positively associated with large trees and medium trees and saplings respectively at the scales of 0-25 m, 0-15 m and 0-40 m, and negatively associated at the subsequent scales. The saplings were positively associated with large trees and medium trees at 0-15 m, 0-25 m respectively, and had no significant association at the subsequent scales. Medium trees showed no significant association with big trees at all the scales. For the dominant trees, the saplings and seedlings of Pinus koraiensis showed negative association at the scale of 0-40 m, while the saplings and seedlings of the three common broadleaved tree species or Ulmus pumila were mainly non-associated. There was a negative association between the saplings of Pinus koraiensis and each size degree of the three common broadleaved tree species or Ulmus pumila at most scale, whereas saplings of the three common broadleaved tree species and Ulmus pumila showed a negative association with non-conspecies only at 0-20 m scale. In the medium and large size degrees, there was no significant association between each two of the three dominant tree species at the scale above 20 m. The secondary forest in Maoershan is still under the process of succession. During the process of forest resource management, measures should be taken to promote the renewal, and the unreasonable spatial pattern should be adjusted in time.