Ditermination of Initial Period of Thing and Intensity Pinus sylvestris var. mongolica Litv Plantation

Pinus sylvestris var.mongolica Litv(Mongolia scotch pine) has become one of the main afforestation species in Fujia State-owned Forestry Farm,Liaoning Province,China.As an important way to regulate the density of stand artificially,selective thinning not only improves the stability of stand,but brings considerable incomes from thinning.In order to improve the quality of Mongolian scotch pine stand,and achieve the goal of fast-growing and high yield,initial period of thinning and related intensities were investigated.The results showed that thinning should be conducted when the tree age was 14-15 years old with a diameter of breast height of 8 cm,in which the competition began among the trees.The thinning could regulate tree density,improve the growth condition of the stand,maintain suitable structure of stand,reduce the period of breeding,and improve productivity.Thinning intensity was 16% to 25% of stem number in the stand,and optimal reserved number of stems was 1 350 to 1 500 per hectare.