Abstract:

The effects of different planting densities (833,1111,1250,1429,1666,2000 and 2500 trees/hm 2) on the growth,output and wood properties of 6-year-old Eucalyptus urophylla were studied by random block experiments in Xiangzhou county,middle of Guangxi.The functional rule and correlation model between the population density of Eucalyptus urophylla and DBH,height,individual standing volume,volume of forest-crop,the air-dry density of wood,form of wood fiber,crown cover,live braches height and rate of preservation have been observed and analysed.The results show that,the effects of density on the DBH,the individual standing volume,the crown cover and the live braches height are extremely remarkable,that on the volume of forest-crop,the width of wood fiber and the length of vessel element are remarkable,and that on the height the air-dry density of wood and the length of wood fiber are not remarkble.According to the results,the limit of reasonable density on Eucalyptus urophylla was suggested to be between 1250 and 2500 trees/hm².2000 trees/hm² is the best density for short rotation industrial forests of Eucalyptus urophylla. The final felling age of the new area in the middle part of Guangxi is 5～7 years.

Key words: Eucalyptus urophylla, Planting density, Growth, Output, Wood properties, Correlation model