Competition Influences Tree Dimension, Biomass Distribution, and Leaf Area Index of Eucalyptus Urophylla in Dryland Ecosystems at East Nusa Tenggara

Abstract

Competition is one of the important factors that determine the productivity of forest stands. However, the effect of competition on the growth dynamics at the individual tree level is rarely documented. This study investigated the influence of competition on the tree dimension, biomass, distribution, and leaf area index (LAI) of Eucalyptus urophylla established in dryland ecosystems in East Nusa Tenggara. Data collection was conducted by N-tree sampling method with the number of center points reaching 36 units. The competition among trees was quantified using Hegyi index. Several parameters were measured to describe tree characteristics, including diameter, height, aboveground biomass, and LAI. The results demonstrated a significant influence of competition on the tree dimension, biomass distribution, and LAI of E. urophylla. The individual tree performance declined along with the increase in competition. By contrast, the increased competition gradually improved the relative contribution of branch biomass to the total aboveground biomass. The exponential model best described the linkage between competition and the tree characteristics of E. urophylla in the study site. Referring to these findings, this study concluded that the growth dynamics of E. urophylla at the individual tree level in dryland ecosystems is substantially influenced by competition.