Experiment on Different Tending Method for Juvenile Chinese Fir(Cunninghamia lanceolata)

The experiment of the effect of different tending methods on the growth andeffect of soil and water conservation were conducted in the juvenile Chinese fir plantation inthe Experimental Centre of Subtropical Forestry,CAF in Fenyi County,Jiangxi Provincefrom 1991 to 1993.The experimental site was located in the central production area of Chinese fir in middle-subtropical zone.There were 12 sample plots in the experimental areawhere the secondary shrubs were distributed before.The soil was yellow soil with a depth of1 m surface soil and 25 cm of humus,and the site index was 16～18.The Chinese fir treeswere planted after burning on the ground.Three tending methods were used as follows:M.1,a thorough weeding without soil-loosening,M.2,a thorough weeding with partial soil-loosening,M.3, a thorough weedingwith soilloosening.The results indicated that the differences of tree growth among themwere not significant.The vegetation biomass of M.3 was less than that of M.1 and M.2(M.1-5.87 t/hm2,M.2-5.89 t/hm2,M.3-4.99 t/hm2).Soil erosion of 1.71 t/hm2 causedby M.3 was the highest,that of M.2,the second,1.15t/hm2 and that of M.1 was 1.08t/hm2.For the consumption of labour,M.1 was the least one of 9.2 labour-day/hm2,M.2 thegreatest one of 16.7 labour-day/hm2,M.3 12.6 labour-day/hm2.Therefore M.1 was themost satisfactory method, which should be adopted on a large scale,especially for the youngplantation without the distribution of Miscanthus floridulus,Imperata clindrica,and Phyllostachys congesta which have to be got rid of from the young Chinese fir stand when they appear.