Abstract: The invention relates to a method of detecting a fire in a wooded area. Some trees in the area are provided with a fire sensor having a radiofrequency emitter able to emit information for identifying and/or locating each sensor, according to a grid of the area to be monitored. At each fire sensor, the fire absent or fire present state is detected A fire sensor emits an alert signal to a monitoring post if a fire is present in the vicinity of the sensor. The alert signal contains information for identifying and/or locating the sensor. The alert signal is transmitted from the monitoring post to a fire brigade by means of a long-range radiofrequency link.