Abstract: The aim of this study is to provide scientific basis for intermediate cutting by determining standard density (stem number) of Chinese fir scenery and recreation forest. Thirty nine sample plots and 2 906 trees of Chinese fir plantation in Jiangle national forest in Fujian province were measured to build crown diameter and diameter at breast height (DBH) and their relationship and analyze the application of the relationship in the forest space, stand density and thinning intensity. The results showed that: the correlation coefficient (R²) is 0.919 5 among 2-43 cm DBH, which was significantly linear. The simulation accuracy among 2-35 cm DBH was high, but among 35-43 cm DBH was low. The analytical result of cd/D in firs of various sizes showed that cd/D decreased gradually with the increase of DBH, and it would finally tend to be a constant.

Key words: Chinese fir, scenery and recreation forest, tree number density, crown diameter(cd), cd/D relationship