In the national park there is a 5000-ha forest of "Calocedrus macrolepis" on limestone ("Calocedrus rupestris") mounts with about 2,500 trees, 600 per hectare. This is the largest forest of this tree in Vietnam. Most of these trees here are 500–600 years old. These trees are listed in group 2A (rare, precious and limited exploitation) of the official letter 3399/VPCP-NN dated 21 June 2002, an amendment to Decree 48 by the Government of Vietnam. Biologists discovered three rare orchid species. Orchids found here include: "Paphiopedilum malipoense", "Paphiopedilum dianthum", "Paphiopedilum concolor". In 1996, IUCN classified these orchid species in danger of extinction in the near future.