Determining Optimum Planting Density of Masson Pine Fast-growing and High yielding Plantations for Various Cultivation Objectives

Data fromspacing experiments and stand density investigation of current plantations were used to determine suitable planting density ofmasson pine (Pinusmassoniana) high yielding plantation and establish adjustment and controlmodels of stand density (A Cmodels)for different cultivation objectives.The results showed thatmiddle planting density with spacing from1.4m×2.0m to 2.0m×2.0m(3555～2490 trees per hectare) was optimumfor high yielding plantation ofmasson pine.A Cmodels for different cultivation purposes were as follows:(1)For cultivating small diameter timber with DBH 12～16 cm,the rotation was 20 years,site index was 14～16,the planting density was 3600～3300 trees per hectare and final remained density 2340～2145 trees per hectare,the annualmean volume increment 11.61～14.54m3·hm-2.(2)For cultivatingmiddle diameter timber with DBH 18～24 cm,the rotation was 25 years,site index was 16～18,the planting density was 2775 ～2490 trees per hectare,the final remained density 1560～1395 trees per hectare,the annualmean volume increment 13.02～17.47m3·hm-2.(3)For cultivating large diameter timber with DBH 26～32 cm,the rotation was 30 years,site index was 18～20,the planting density was 1995～1725 trees per hectare,final remained density 900～750 trees per hectare,and the annualmean volume increment 16.20～16.76m3·hm-2.