ISSN 2375-1096
International Journal of Agroforestry and Silviculture ISSN 2375-1096 Vol. 6 (1), pp. 326-336, January, 2018. © International Scholars Journals
Full Length Research Paper
A study of five rare tree species in forests on limestone hills of northern Vietnam
*Arun Akram1, Nalini Bijoya1 and Soham Anirvan2
1Department of Silviculture, Faculty of Agricultural Sciences, University of Göttingen, Göttingen, Lower Saxony, Germany.
2Department of Agronomy, Faculty of Agricultural Sciences, Nutritional Sciences and Environmental Management, University of Giessen, Gießen, Hesse, Germany.
Corresponding author. E-mail: [email protected]
Accepted 08 April, 2015
Abstract
Rare tree species may become endangered as a result of forest conversion and disturbance. The availability of reliable ecological information on such tree species may help in conservation efforts, but such data is often limited. We studied the abundance of five red-listed tree species in an old-growth forest growing on limestone hills in northern Vietnam and identified potentially relevant ecological factors. Three of the studied species are largely restricted to limestone hills and regarded as specialists (Excentrodendron tonkinense, Chukrasia tabularis and Garcinia fagraeoides), while the two other species (Parashorea chinensis and Melientha suavis) are more widely distributed. The study species were recorded across 40 initial random plots at a range of frequencies (13 - 60%) and at relatively low stem densities (0.4 - 4% of the total stems). Using the adaptive cluster sampling method (ACS), we found all species to be relatively abundant across the site. The density of the three specialist species tended to increase from lower to upper slope positions, which was consistent with an increase in rock-outcrop cover, steepness of the slope, and a reduced soil depth. However, even on rocky, steep sites we found a high variation in tree densities of these species among plots, which could not be explained by the recorded ecological factors. The non-specialist species did not occur on mostly rocky sites. We regard these results as a potential baseline from which impacts of logging can be addressed and to inform potential management.
Key words: Adaptive cluster sampling, biodiversity conservation, endangered species, karst, red list, regeneration, tree ecology.