Research on selection of plus trees of Xylia xylocarpa (Roxb.) Taub.) in south central and central highlands provinces

Abstract

Xylia xylocarpa (Roxb.) Taub. is a rare and precious tree species, with hard, strong wood, distinct sapwood and heartwood, light yellowish - white sapwood, thick, dark red heartwood with slightly grained, very smooth, heavy. The research on selecting superior Xylia xylocarpa trees was conducted in 2023, aiming to select superior Xylia xylocarpa trees with good productivity and trunk quality to serve large timber plantations in the provinces of the South Central and Central Highlands regions. The results of the selection survey in 5 provinces have officially selected 118 superior Xylia xylocarpa trees from 144 selected trees, of which: 16 trees originated from Gia Lai province, 20 trees from Dak Lak province, 30 trees from Ninh Thuan province, 26 trees from Binh Thuan province and 26 trees from Khanh Hoa province. The selected superior trees in the 5 provinces all grew and developed well, with diameter at breast height (D_1.3) ranging from 23.6 – 52.5 cm, height from 17.0 – 25.5 m, height below the large branches, reaching from 12.0 – 19.0 m, accounting for 53.3 – 83.3% of the height at the top, canopy diameter from 5.5 – 9.6 m. The superior trees had a relatively high total trunk quality score, from 13 - 15 points/tree. The superior Xylia xylocarpa trees were monitored for reproductive cycle and collected for seeds to provide a source of seeds with improved yield and quality, contributing to the exploitation and development of valuable rare plant gene sources in the provinces of the South Central and Central Highlands regions.