Abstract: Based on the branch analysis data of 30 sample trees from 6 permanent plots in Mongolian pine (Pinus Sylvestris var. mongolica) plantation, the predicting models of crown surface area and crown volume were developed according to power function as base model by analyzing the relationship between crown surface area and crown volume with stand and tree variables. Also, the correlation between volume increment with crown surface area and crown volume were analyzed. The result showed that crown surface area and crown volume are increasing with DBH, total height, and crown length and the volume increment of tree is significantly linear correlated with crown surface area and crown volume for Mongolian pine plantation. For different stand conditions, crown surface area and crown volume were increased with stand age and DBH. The crown surface area was decreased with stand density and the relationship between crown volume and stand density was not significant. The predicting models of crown surface area and crown volume developed in this paper were evaluated. The test results indicated that relative mean errors in predicted stand attributes were less than ±8% and the estimated precisions of the stand variables were all greater than 91% for each model. Therefore, the models developed in this paper are suitable for estimating the crown surface area and crown volume under different stand conditions for Mongolian pine plantation.

Key words: Pinus sylvestris var. mongolica, crown surface area, crown volume, volume increment