Thinning Effect on Growth of 4-year-old Eucalyptus urophylla Plantation

4-year-old E.urophylla plantations were thinned by different intensity,their growth were investigated after two years.The results showed that thinning had significant effects on mean diameter at breast height(DBH) and individual volume;but thinning effect on tree height was not significant,which could promote tree height growth.The more thinning intensity,the more increment of individual volume .There were significant differences in MAI (Mean Annual Increment) of plantation among 3 thinning intensities.According to total volume and MAI,thinning intensity of 60% was the best treatment in this experiment.