GROWTH AND PRODUCTIVITY OF SOME Acacia auriculiformis CLONES PLANTING ON ACID SULFATE SOILS IN U MINH HA REGION, CA MAU PROVINCE

Abstract

The demand for timber resources in Vietnam’s wood processing and forest product industries has been increasing rapidly, while the domestic supply of large-sized timber remains insufficient. Acacia auriculiformis is a major plantation tree species with high productivity, good wood quality, and broad adaptability to diverse ecological conditions. However, A. auriculiformis clones developed in recent years have not yet been comprehensively and systematically evaluated for growth and productivity under acid sulfate soil conditions typical of the Mekong Delta. Therefore, this study was conducted at the U Minh Forestry Experimental Station, Ca Mau province, to evaluate the growth and productivity of selected A. auriculiformis clones on acid sulfate soils, providing a scientific basis for tree improvement and the development of large - sized timber plantations in the region. After 42 months, significant differences in growth and yield were observed among the tested clones. Three clones Clt57, Clt98, and Clt26 demonstrated superior performance, achieving mean annual increments of 34.1 to 35.5 m³ ha⁻¹ year⁻¹, representing a 20.7 - 25.7% increase compared to the overall trial mean and outperforming previously reported yields in other ecological regions. In addition, these clones exhibited high survival ( 82.5 – 92.1%), relatively straight stems, fine branching, and low incidence of pests and diseases, thereby meeting the criteria for extended recognition under Vietnamese Standard TCVN 8754:3, contributing additional improved planting material for large - sized timber plantations in the U Minh Ha region, Ca Mau Province, and areas with similar site conditions.