Abstract: In Hongchiba region of Wuxi County,the controlled burning and aerial sowing in 1972 rehabilitated degraded forest vegetations,and various types of Pinus armandii mixed communities were formed.By employing Petraitis' general and specific overlap indices,this paper analyzed the resources utilization of 10 main tree populations in Pinus armandii mixed forest.The results showed that Pinus armandii and most native trees had a wide niche breadth,and the interspecies general overlap value was 0.728,indicating that there was a fully and effective habitat resources utilization in the communities. The interspecies specific overlap value of Pinus armandiioverlapping other native trees was very low,while that of native trees overlapping Pinus armandii was quite high,which demonstrated that the resources utilization and competition capability of Pinus armandii were weaker than those of native trees,and Pinus armandii population was at its inferior state during the process of their competitions.The interspecies specific overlap value between native trees was very low,generally because of their sound niche differentiation on resources utilization.As a result,the niche characteristics of native trees should be regarded as a favorable sample for the application of ecological rehabilitation and reconstruction.The advantages and disadvantages of Petraitis' overlap indices were discussed in this paper preliminarily.

Key words: Quantitative Theory Ⅰ, Artificial pastureland, Forage, Weed