Abstract:

Forest succession direction was an important work for natural forest management. This paper presented a new index which named natural compose index and this parameter could be used to express the difference between forest succession and the progressive succession. After making a comparison between reference trees and neighbouring trees on advantage of growth and succession level, the advantage of trees in different succession level and natural compose index could be gotten. Castanopsis sclerophylla mixed stand in Guihua Forest Farm in Hubei has been taken as an example. The new index was used to calculate and adjust in mixed stand. The mean natural compose index of this stand was 0.76, and the succession trend of this stand was progressive succession, natural compose index of 4 sample plots were respectively 0.65, 0.83, 0.79, 0.76.Combined with the analysis of different tree species, we could know that the mean natural compose index of spatial structure units whose reference tree were Castanopsis sclerophylla, Cunninghamia lanceolata, Pinus massoniana were high, this one showed that the succession trend of these spatial structure units were progressive succession, and only small parts was regressive succession; the mean natural compose index of spatial structure units whose reference tree were Liquidambar formosana, Quercus chenii were low, although the succession trend of these spatial structure units were progressive succession, more spatial structure units' succession trend were regressive succession. These spatial structure units should be timely structural adjustment, and made the forest succession direction closer to progressive succession.

Key words: natural compose index, succession, Castanopsis sclerophylla, competition index