Diversity and Succession of Perennial Trees in the Rehabilitation Areas of a Limestone Mine, Saraburi Province, Thailand

This study aimed to investigate the structure and composition of plant community to i) identify tree species that can colonize, grow, and form communities and ii) identify species under natural succession whose seedlings can be used in forest rehabilitation. Experimental plots of size 40 m × 40 m were established in 13-, 10-, and 5-year-old rehabilitation areas (13YRA, 10YRA, and 5YRA), where characterized as flatted, sloped, and benched areas, respectively. The survey found 24 genera, 12 families, and 25 species of plants. Plant species that were found in all plots were Zollingeria dongnaiensis Pierre., Pterocarpus macrocarpus Kurz., Albizia lebbek (L.) Benth., and Azadirachta indica A. Juss.) which can potentially grow well in several conditions of post-mining areas. The 13YRA plot had the most significant number of naturally regenerating species (11 species) as the area was next to a natural forest or buffer zone and had been under restoration for the most prolonged period. The community succession of the rehabilitation plots relative to the natural forest was relatively slow. Nonetheless, the pioneer species can help to improve the environmental factors to optimum levels for the natural succession of the plant community. This can also be useful while selecting pioneer species for restoring areas previously used for limestone mining and help reduce the time for succession in terms of increasing the species composition.