A STUDY ON THE ADAPTABILITY AND GROWTH OF SOME TROPICAL ACACIAS IN SOUTH CHINA

The tropical acacias are multipurpose trees. Most of them are fast-growing and they have strong adaptability in different soils in the tropical and south subtropical zone of China. At 3~4 years old, the mean annual increament of Acacia mangium and A. crassicarpa reached 2-4 m in height and 3~4cm in D. B. H.. The low temperature is a limiting factor in planting acacias. Their northern boundary of cultivation can reach 20℃ isotherm, some sites may be extended to 18℃ with an annual accumulated temperature of more than 7000℃, absolute minimum temperature is above 5℃. This is the suitable range for planting tropical acacias.Owing to a lot of acacias play a good role for agroforestry, soil improvement and nitrogen fixation, a higher benefits of socioeconomy may easily be achieved by planting tropical acacias. There are a great many of acacias' timber suitable for construction, furniture and veneer etc., its basic density is between 460~620 kg/m3. They can be used as good quality pulpwood of broad-leaved trees.