Assesement of growth of 11 - year - old Acacia auriculiformis plantation for saw - log production in Dong Nai province

Abstract

This study used an Acacia auriculiformis plantation planted in 2002 by the National projects KC.06.05.NN to evaluate the possibility of providing saw timber after 11 years of planting at Song May station (Dong Nai province). The planted clones had clone certification, including A19, A58, a33, a147, which were mixed in the ratio of 1:1:1:1 when planted. The treatments were of factorial design, with different amounts of NPK fertiliser (14:8:6) and biofertiliser (Song Gianh) applied to each tree at planting, and additional -fertilising in years 2 and 3. Two years after planting, the highest growth rate was in the treatment group which received 150 - 200g NPK and 200 - 300g
biofertiliser at planting. After three years, the best treatment of additional fertilising at year 2 and 3 was 200g of NPK fertilizer and 200g biofertiliser. Planting densities were 1,110 and 1,660 trees/ha -1. After 11 years the density, standing volume and MAI were 1,020 and 1,270 trees/ha -1, and 300.5 and 300.9m3
ha -1, and 27.3 - 27.4m3 ha -1/year -1, respectively. Growth
rate, annual increament of standing volume and proportion of large - size timber of individual were significantly higher in the density treatment of 1,110 trees/ha -1. Where the initial planting density is 1,110 trees/ha -1, after 11 years the proportion of trees having diameter at breast height over 18cm was 48.4%, white it was 31.4% in the density 1,660 trees/ha -1.