Investigation on Effect of Forestation by Mixing Pinus massoniana with Schima superba

Since forestation of pure forest of Pinus massoniana is liable to suffer from pest calamity, soil erosion, decrease of soil fertility, and difficulty in wood production in the hilly areas of southern China, we conducted an investigation on the three types of forests in Gao'an County of Jiangxi Province, namely, the pure forest of Pinus massoniana, the pure forest of Schima superba, and the mixed forest consisting of the two species, setting up standard stand, measuring and studying the growing stock, biomass, leaf area, roots,soil, vegetation, pests, litters, soil erosion, microclimate, etc., with the following results. ① The average height, diameter at chest height, and volume of the mixed forest are higher than those of the pure forest of Pinus massoniana by 30.9%, 31.7% and 10.6%, respectively. ② The biomass of the mixed forest is 2.24 times as much as that of the pure forest of Pinus massoniana. ③ The litters of the mixed forest is 3.37 times and 1.96 times as much as the litters of the pure forest of Pinus massoniana and the pure forest of Schima superba respectively. ③ The occurrence of pest calamity per tree is lower and the conditions of soil erosion and microclimate are better than those of the pure forest ofPinus massoniana. ④ The mixed forest of the two species is an excellent mixed type of needle-leaf and deciduous forest worth being popularized in China's subtropical areas, especially in the low hilly areas. It is recommended in plantation that the mixed patterns be between trees, lines, small blocks, or scattered-dots, the ratio of mixture of Pinus massoniana and Schima superba be 5 to 1, or 3 to 1, and the initial space between trees be 1.2, 1.5, or 2.0 m while the initial density be 6 944 to 4 440 trees per square hectare.