Abstract:

Crown ratio models for 10 dominant species in Mao'er Mountain experimental forest station located in Heilongjiang Province were developed and the study is part of a project to develop the protection demonstration and sustainable management techniques for natural forest in northeast China. Thirty permanent sample plots were established and 3 628 of 4 237 sample trees were used to develop the crown ratio models in 2007. The models developed with Logistic function were designed from size, competition and site to explain the crown ratio and unadjusted multiple coefficient of determination was used to evaluate the percentage of variation explained by three variable groups. The estimation results of the models indicated that the total percentage of variation explained by variable groups ranged from 12.881 3%(Acer mono) to 42.116 8%(Betula platyphylla), and the percentage was 17.403 2% for Tilia spp, a widest-distributed species in this area. Validation for the crown ratio models showed relatively high prediction precision and low errors.

Key words: crown ratio, secondary forest, Logistic equation