Differentiation Characteristics and Their Effects on Productivity with Different Planting Densities of Pinus massoniana Plantations

【Objective】To study the characteristics of individual differentiation and its impact on productivity in the growth process of different densities of Pinus massoniana, it provides a basis for determining suitable management densities, cultivating large-diameter woods and improving stand productivity in P. massoniana forests.【 Method】 Based on 15 continuous years observation data of four kinds of P.massoniana plantations with planting density of 2 500, 3 333, 4 500 and 6 000 plants·hm-2（denoted as: A, B, C, D）, and random forests and structural equations were used to explore the influence of forest age, planting density and self-thinning process on individual differentiation and productivity of P. massoniana forests.【Result】Gini coefficient（individual size differentiation） decreased significantly with increasing stand age and increased significantly with increasing density. In the process of stand self-thinning, the number of standing trees decreased significantly with the increase of stand age,and the self-thi