Structure and composition of tree and shrub species and their invasiveness in conservation areas of West Timor, Indonesia

Abstract

Abstract. Lumban-Gaol M, Mudita IW. 2023. Structure and composition of tree and shrub species and their invasiveness in conservation areas of West Timor, Indonesia. Asian J For 7: 132-144. This study aimed to investigate the composition of vegetation of tree and shrub species and their invasiveness in West Timor conservation forests, Indonesia. Three conservation zones were purposefully chosen to showcase Timor Island's conservation forest. Baumata Nature Recreation Park (Baumata NRP), Camplong Nature Recreation Park (Campong NRP), and Herman Yohannes Grand Forest Park (Herman Yohannes GFP) are three such parks. The point-centered quarter approach was used to collect data. The Important Value Index (IVI) was established for each existing species. Each plant was classed as either invasive or non-invasive. Approximately 59 tree and shrub species were found in these three conservation zones. Based on IVI, the forest was dominated by Cassia siamea Lam. (23.53%), Tectona grandis L.f. (21.97%), Schleichera oleosa (Lour.) Oken (19.61%), and Syzygium aqueum (Burm.fil.) Alston (14.95%). More than 40% of the species present were potentially invasive. Based on the IVI, the potentially invasive species were dominated by C. siamea (23.53%), Tamarindus indica L. (11.69%), Gmelina arborea Roxb. ex Sm. (10.73%), Swietenia macrophylla G.King (10.30%), Ficus benjamina L. (7.45%), Antidesma bunius (L.) Spreng. (7.40%), and Albizia Durazz. (7.31%). The presence of invasive trees and shrubs in the conservation area of West Timor was relatively high. Therefore, it requires management actions to prevent further spread and dominance.