Abstract: Abstract: The study on the combustibility of tree species is the basis of forest fuel treatments. The cone calorimeter was used to measure the combustibility of dead branch of 2~4 mm, 5~8 mm and 9~12 mm diameters of 9 tree species and Eupatorium adenophorum in central Yunnan. The single combustibility was analyzed, and the results were as follows: Time to ignition, combustion duration, time to peak heat release rate and time to peak effective heat combustion increase with the increase of the diameter of branches. Peak heat release rate and peak mass loss rate of every tree species decrease with the increase of branch diameter. When the diameter of branch was smaller, peak heat release rate and peak mass loss rate were more obvious, and with the increase of diameter, peak heat release rate and peak mass loss rate became less obvious. Peak effective heat combustion and peak specific extinction area have little correlation with the diameter of dead branches. Time to peak mass loss rate of different tree species increases with the increase of branch diameter. Time to peak specific extinction area of Eucalyptus robusta decreases with the increase of branch diameter，but other tree species increases with the increase of branch diameter. Compared with 9 tree species, the time to ignition, duration of combustion, time to peak heat release rate, time to peak effective heat combustion, time to peak mass loss rate and time to peak specific extinction area of Eupatorium adenophorum are the lowest，and it is easy to burn and to lead to crown fire. The peak heat release rate of Sabina chinensis and Cupressus torulosa were high, while the ignition time and peak heat release rate of Pinus armandii and Pinus yunnanensis were small. These 4 tree species have high flammability and are easy to cause continuous crown fire, and the fire intensity is large and easy to cause large losses. In the process of forest fuel treatments, the dead branches, especially those with small diameter, should be cleaned up in time.

Key words: Key words: tree species, combustibility, cone calorimeter