Abstract:

Competition is a vital factor to affect tree growth. Competition among trees includes aboveground and underground parts. The zone which influence the competition among trees were divided into two parts: one part was defined as inside radius in which the near trees contact by crowns and roots and the competition effect among them includes aboveground and underground parts, another part was defined as outside lane where the competition among trees came from underground. At the same time the competition index components were divided by different competition tree species, then the model of competition index was constructed. Taking each component of competition index as independent variables and the yearly volume growth as dependent variable, the competition-growth model was established with good regression result. The study provides the scientific basis for the theory research and reasonable management of Casuarina equisetifolia and Pinus elliottii mixed stand.

Key words: Competition index, Competition effective model, Casuarina equisetifolia, Pinus elliottii, Pure stand, Mixed stand