Study on the Initial Planting Density of Industrial Timber Stands of Slash Pine and Loblolly Pine

The test stands were established at five sites in the central and north subtropical region of China in order to determine the suitable initial planting densities of industrial timber plantation of slash pine and loblolly pine.According to 6～7 years’ field survey results the effects of initial density on the stand factors of individual tree growth,population development,tree form and wood property,and the changes of growth factors due to the difference of stand development process were analyzed.Based on the comprehensive consideration of biological and economic factors,the initial planting density patterns is suggested as follows:with the site index of 14～18,the densities are 2 000～1 333·hm-2 for slash pine,1 667～1 111·hm-2 for loblolly pine.The densities of 2 000～1 667·hm-2 are adopted for unthinning pulping timber stands,or compound target of pulping timber and middle dimension timber with thinning;1 667～1 111·hm-2 and thinning are adopted for cultivation of middle and large dimension timber. Meanwhile,the necessary cultural measures are put forward for the realization of above management goals.