Plus tree selection of Gao vang (Naucleo Orientalis) for big timber developing of indigenous plantations

Abstract

The results of early growths assessment of the Gao vang experimental planting area at the stage 7 year old and the selection of plus trees for big timber plantations show that the average growths in diameter at breast height, crown diameter, total height and trunk volume of plus trees (TG) reached a value of 16.74 cm; 5.24m; 10.74m; and 118.20 dm3 per tree, respectively, exceeding the accompanying forest tree group (ĐR) of 1.60; 1.02; 1.15; and 2.82 times, respectively, under the same comparison criteria, environmental conditions and time. The forest tree groups including, ĐR1; ĐR2; ĐR3; ĐR4; and ĐR5 had a coefficient of variation (CV%) in diameter of 19.07; 18.41; 13.45; 17.90; and 17.18%. Growth speed in diameter of plus trees including, TG4; TG3; TG2; TG5; and TG1 reached a value of 2.31; 2.40; 2.40; 2.41; and 2.43 cm per year, respectively, growth farther other forests tree group by 1.55 to 1.59 times. Exceed level (%) in diameter of plus trees including, TG1; TG2; TG3; TG4; and TG5. Forest trees groups reached a value of 31.75; 30.72; 31.97; 31.52; and 30.89%, respectively, that were better than the accompanying forest tree groups and the standards of plus trees for big timber indigenous plantating development. In total, there are over 1360 Gao vang individuals measured and evaluated, but only 5 excellent trees in growth could be selected, that had a exceed level for diameter of over 30% compared to the accompanying forest tree group, a ratio of 0.36%, and a selective intensity of 0.99. The plus trees evaluated and selected are very valuable as propagation materials, contributing to providing information, scientific basis, quality seed sources, and diversifying the structure of forestry tree varieties for the goal of developing big timber plantations with native species.