Structural Characteristics of Natural Limestone Forests in Cat Ba Biosphere Reserves, Vietnam

An ecological understanding of natural forests after anthropogenic intervention is important for sustainable forest management. This study analyzed the overstory characteristics (species composition, growth, and diameter distribution) and regeneration (species richness, density, and height distribution) in natural limestone forests in Cat Ba Biosphere Reserve, Vietnam. Data were collected in nine study plots established in selective-logged (SLF), clear-cut (CCF), and unlogged (UF) forests. Results indicated that the overstory characteristics of SLF and CCF were lower than that of UF (species richness was 33 in UF, 20 in SLF, and 16 in CCF; DBH was 20.6 ±13.7 cm in UF, 16.9 ±9.7 cm in SLF, and 10.5 ±3.8 cm in CCF; Basal area was 38.2 m2 ha-1 in UF, 24.0 m2 ha-1 in SLF, and 11.4 m2 ha-1 in CCF). For regeneration, species richness also varied from UF (25) to SLF (13) and CCF (5), while seedling density reversely increased. We concluded that a 20-year restoration was insufficient for artificially disturbed forests to recover their ecological functions, regardless of logging intensities and techniques applied.