A Comparative Study on Understorey Vegetation Diversity in Eucalyptus Plantations in Hainan Island

摘要

Eucalypts are widely planted in southern China, but stands have a simple structure and poor diversity of understorey vegetation. Understorey vegetation is an important component of the artificial plantation ecosystem, playing a role in maintaining soil fertility (MaoheYao et al. 1991; Yu Xuebiao 1999). Growing volume and biomass of 4.5-year-old eucalypt plantations decreased with successive rotations (Yu Xuebiao 1999). Biodiversity also decreases with continuous planting, and understorey vegetation is a component and technical link in management and sustainable development of forest plantations. This short communication summarises research to identify critical factors that influence understorey vegetation diversity on the basis of comparative analysis of the flora component species and the diversity of understorey vegetation. The research aimed to provide a basis for developing understorey vegetation in eucalypt plantations and a theoretical basis for their sustainable management. Research was conducted in 14 counties as well as Haikou city, Qiongzhong, Baisha, Tongzha, and Baoting County of Hainan Island (latitude 10°09′-20°10′N, longitude 108°03′-110°03′E). Eucalyptus plantations investigated in 14 counties covered 3000 ha. The climate of the area is monsoonal, with the annual sunshine of about 2500 hours, annual mean temperature 23-26℃, and annual mean rainfall 1000-2500 mm. The soils are lateritic.