Differences in the structure, species composition and diversity of primary and harvested forests on Changbai Mountain, Northeast China

Broadleaved-Korean pine (Pinus koraiensis) mixed forest is a typical vegetation type in the eastern Eurasian continent. We compared the structure, composition and diversity of a primary forest and a logged forest for effective management and regeneration of a mixed forest ecosystem on Changbai Mountain, Northeast China. The logged forest was subjected to selective harvesting twenty years ago. The mean diameter and basal area for overall trees (≥ 2 cm dbh) were higher in the primary forest than in the logged forest, whereas overall tree density was significantly lower in the former (994 ± 34 trees∙ha-1) than in the logged forest (1921 ± 79 trees∙ha-1). The values of species richness and both Simpson's and Shannon's diversity indices for seedlings (< 2 cm dbh, ≥ 50 cm tall), saplings (2-9.9 cm dbh) and overall trees were greater in the primary forest. These results indicate that the selective logging had a lasting impact on the structural characteristics of the forest. There were major differences in species composition between the two forest sites, with the logged forest having more pioneer and mid-tolerant species than the primary forest. Diversity was more extensive in the logged forest due to the invasion of pioneer species. Twenty years is clearly an insufficient time for the logged forest to regain "primary" forest composition and structure. These two characteristics of the primary forest may serve as a reference for developing management plans for forest regeneration.