Nakhon Si Thammarat province is located at Lat 8-10 degrees N and Long 99 degrees 15′ to 100 degrees 5′E. The mean annual rainfall is 2,429.04 mm. Nakhon Si Thammarat has mangroves about 246.339968 km2 in district of Mueang Nakhon Si Thammarat, Khanom, Pak Phanang and Tha Sala. More than a half of area was changed to agriculture, shrimp farm and port. The dominant trees are in family Rhizophoraceae and Acanthaceae.