Abstract: Abstract: For single?phase tree ignition of vegetation and thus forest fires, in order to clarify the ignition characteristics and temperature rise mechanism of vegetation, this paper laps the test platform to conduct a study of the wire contacting pine trees and analyze the ignition phenomenon and temperature change during the ignition of vegetation by the wire contacting the tree. The analysis found that the vegetation ignition is divided into four stages: initial contact, water evaporation, carbonization channel, and spreading through; meanwhile the leakage current is also affected by the temperature showing obvious characteristics of the four stages of development; the heat of the vegetation temperature rise comes from the thermal effect of the current and heat transfer from the object. Further, according to the heat action path and temperature rise mechanism, the temperature rise model of calculating ignition point?time is proposed to predict and analyze the open flame time of vegetation spreading to different locations. The validation results show that the calculated model has high accuracy and is important for guiding the prevention and control of forest fires started by wire.

Key words: single?phase contact trees, forest fires, ignition characteristics, temperature rise model, open fire time