Abstract: The intraspecific and interspecific competition intensities in the secondary Acer mono forest were quantitatively analyzed by Hegyi single-tree competition index model. The results showed that the intraspecific competition intensity in A.mono was bigger, accounting for 26 percents of total competition, and the competition intensity gradually increased with the increasing tree diameter. However, the competition intensity decreased after diameter at breast height DBH was greater than 30 cm. The interspecific competition (89.061) in A.mono was more intensive than the intraspecific competition (31.487). The competition intensity of interspecific competition with A.mono followed the order of A.mono>Tilia mandshurica>Quecus mongolica>Phellodendron amurense>Juglans mandshurica>Tilia amurensis. The competition intensity of A.mono declined with the increasing DBH, and the stress was more intense for trees less than 15 cm in DBH. The relationship between competition intensity and DBH of target trees followed the exponential function. The tending management should be actualized to increase the timber utilization quotiety when DBH of A.mono individual near 15 cm in natural conditions.

Key words: Acer mono, secondary forest, intraspecific competition, interspecific competition, competition index