A sensor module is assigned to a vehicle (1, 9) that can be displaced in a terrain or designed for being positioned in the terrain. The sensor module has a sensor system with sensors (7) that acquiresensor data in a contactless fashion. The sensors (7) are designed for detecting the spatial extent of the plant at a location in the terrain. The sensor data makes it possible to determine whether the plant should be pruned. To this end, the sensor data is evaluated by utilizing a knowledge database.