Abstract: Excentrodendron hsienmu is a characteristic species in karst seasonal rain forest, and thus, to study the age structure and survival status of E. hsienmu population can provide insight into the succession process and status of karst seasonal rain forest. Based on the investigation data from a 15 hm² plot in a karst seasonal rain forest at Nonggang of South China, and by using quantitative analysis method, this paper studied the age structure and quantitative dynamics of E. hsienmu population in the forest. In the forest, E. hsienmu population was characterized by the abundance of young individuals, and the age structure of the population was in an inverseJ shape. The survival curve of the population could be described by the Deevy Ⅱ curve and Deevy Ⅲ curve, but more appropriately by Deevy Ⅱ curve, which implied that E. hsienmu reproduced a large number of offspring to maintain its population. There existed two peak phases of mortality rate in the population lifespan, i.e., 0-9 and 60-69 years. The survivability of the population had the characteristics of fluctuated at young age, stable at middle age, and decline at old age. The quantitative dynamics of the population had no obvious large cycle fluctuation, but a small cycle (about 11 years) fluctuation. In conclusion, the E. hsienmu population in the karst seasonal rain forest was of an expanding structure, and the survival status of the population fluctuated across different life stages, with a relatively high mortality rate at young and mature stages. The age structure and quantitative dynamics of the population could be greatly affected by the biological characteristics of the population itself and by the restrictive effect of negative density as well as the karst geological drought.

Key words: fuel, thermogravimetric analysis, flammability, combustibility, sustainability., ignitibility