Abstract:

Aims Our objectives were to investigate the inter- and intra-specific interactions of trees in a natural Pinus kesiya forest after three different selective logging disturbances, and to examine the impact of selective logging on disturbance intensity for sustainable forest management.

Methods Niche breadth, niche overlap, interspecific associations, Hegyi’s single-tree competition index model and M. Godron methods were used to analyze the inter- and intra-specific interactions of trees based on the field data collected from 81 small quadrats in nine plots in a natural P. kesiya forest in Jinggu County, Yunnan Province.

Important findings (1) Selective logging disturbance changed the relative dominance of most tree species except P. kesiya. The niche breadth of P. kesiya population increased with increases in disturbance intensity. The niche breadth was greatest in P. kesiya and Schima wallichii among all tree species under a severe disturbance. (2) The interspecific relationship of tree populations changed was affected by disturbance intensity. The niche overlap in the intermediate disturbance communities was apparently higher than those without disturbance or under a severe disturbance. In all the three communities, the niche overlap between P. kesiya and other tree species was very small. The proportion of species pairs with positive and negative associations became gradually increased with increases in disturbance intensity. 3) Hegyi’s competition index showed that the main competitive stress of P. kesiya population mainly came from inter-specific competition. Disturbance intensity increased the inter-specific competition between P. kesiya and other trees, and the mean competition index decreased with increasing diameter at the breast height in P. kesiya. 4) The formation of forest gap was the main reason for changes in inter- and intra-specific relationships of P. kesiya forest. Although all communities were unstable under different disturbance intensities, species richness and community stability were both higher when under intermediate disturbance compared with no or severe disturbances. The principle of selective logging should be determined by the aim of forest management, which should be considered as the basis for timber production and forest ecosystem service.

Key words: community stability, competition index, disturbance, importance value, interspecific association, niche