On the Thinning Scheme for Industrial Timber Stands of Slash Pine and Loblolly Pine

Thinning density tests were established in 10 plantations of 6～18 years old slash pine (Pinus elliottii) and loblolly pine (Pinus taeda). Based on the response of stand growth factors to the treatments after 4～6 years and the economic analysis results, the stand density regulating schemes of the two species were determined. According to the the operating results, it is that under the normal conditions, thinning will have net profits in the stands over 8 years old with density below 2000 trees·hm-2,and the time of first thinning must be before 12 years so the growth rate of reserved trees could be improved. By thinning, the outturn percent of merchantable timber of standing trees are slightly increased, bu the growing stock and total yield of stands are decreased along with the increase of thinning density, the interval of thinning should be at least 6 years or longer. With comprehensive consideration of the factors including site conditions, treatment effects and management targets, the cultivation schemes wrer put forward. The establishment of industrial timber plantation with the two species should be on the site with site index of 14～18. For the pulping timber cultivation, the stand should be planted with density of 2000～1667 trees·hm-2, harvested at about 15 years old, or thinned to about 1200 trees·hm-2 at 8～10 years old and final cut at 18～20 years old. For construction timber cultivation, the planting density should be 1667～1111 trees·hm-2, the first thinning should be operated at 10～12 years old with the reserved trees of about 1100～800 trees·hm-2, the second thinning should be at 16～18 years with 800～500 trees·hm-2 reserved, the final cut be at 20～25 years old.