Abstract: In this paper, the leaves and twigs of eight typical tree species in central Liaoning were selected as the research objects. The electric blast drying oven and cone calorimeter were used to measure 11 indexes affecting their combustibility. The indexes were classified from three characteristic dimensions of ignitability, intensity and persistence, and the three-dimensional combustibility evaluation was carried out by grey correlation analysis. The results showed that the water loss efficiency of the combustible materials of leaves and twigs increased with the heating time. The heat required for igniting leaves was much greater than that of twigs. The moisture content of coniferous species was larger, and the leaves were more flammable than twigs. The intensity and persistence of the eight trees were positively correlated, and the correlation between ignitability and intensity was weak. The comprehensive combustion activity of Pinus tabulaeformis, Betula betula, Quercus mongolica, Pinus huasanensis, Cottonwood, Ash, Cotinus and Ginkgo was weakened successively.

Key words: tree species, combustibility, water loss efficiency, extinguish moisture content, grey correlation analysis