THE GROWTH REGULATION OF GMELINA ARBOREA

The result of the research shows that the Gmelina arborea has two fast-growing period on growth of tree height and diameter in natural forest, the first one appears in the tenth year and the other one appears in the fortieth-fiftieth year. The volume growth is still increasing and lasting to as long as fifty or sixty years old. If the sowing is in proper season, the growing peak of height and diameter of seedlings appear in the third month after sowing, but decreases immediately. The growing peak period of height appears in the second to fifth(sixth) month and it's increment is up to 79-90% of the total of one year. There are two growing peak period of seedling diameter growth, the principal one appears in the second to fourth(fifth) month and the secondary one in the seventh month after sowing, the increment of the two period is up to 72-80% of the total; In the young plantation of eleven years old, the growing peak of tree height, diameter and volume appear respectively in the second, fourth and seventh year after planting, the speed of height growth decreases in the eighth year but the increments in diameter and volume are increasing rapidly in this period.