1. A method of detecting smoke of a forest fire using spatiotemporal Bag-of-Features (BoF) of the smoke and a random forest, the method comprising the steps of: (1) whenever each frame of a video sequence is input, detecting a difference between the input frame and a previous frame, and setting the input frame as a key frame if the difference exceeds a predetermined first threshold value; (2) detecting one or more moving blocks in the set key frame; (3) extracting one or more candidate smoke blocks from the moving blocks using a smoke color model; (4) generating BoF representations from the detected candidate smoke blocks; and (5) determining whether smoke of the candidate smoke blocks is actual smoke by performing random forest learning on the generated BoF representation.