The Mo Singto forest dynamics plot, Khao Yai National Park, Thailand

A permanent biodiversity research and monitoring plot has been established in the center of Khao Yai National Park, east-central Thailand. It is located in broad-leaved, seasonal evergreen forest (725–815 m altitude) in the Mo Singto area which has been a study site for white-handed gibbons (Hylobates lar) since 1979. The plot is 30 ha in area and has been surveyed into 20-m squares and mapped with ArcGIS. Every woody stem ≥ 1 cm in diameter at 1.3 m height was measured, mapped and identified during 2004–2005. There were a total of 262 species of trees and shrubs ≥ 1 cm in diameter and 204 species ≥ 10 cm in diameter. Approximately 120 species of woody climbers ≥ 3 cm in diameter have been identified and counted. The plot is used for the study of the diversity and dynamics of tree populations and plant-animal interactions. Of particular interest has been the role of mammals and birds in the dispersal of seeds, their germination, and the survival of seedlings. Gibbons continue to be a focus of research, and their diet, foraging behavior and importance to fruiting trees and lianas are the subjects of long-term study. Bird populations and their breeding behavior and ecology are also being studied. The plot has played a vital role in the training of graduate students pursuing master’s and doctoral degrees in biology and environmental science. The Mo Singto Plot is now part of the global forest dynamics plot network of the Center for Tropical Forest Science (CTFS), Smithsonian Tropical Research Institute.