Foresters and ecologists argue that large controlled burns in Yellowstone prior to the fires would not have greatly reduced the area that was consumed in 1988. Controlled burns would quickly become uncontrolled if they were allowed to burn with the intensity that many tree and plant communities need for proper regeneration. Consequently, natural fires, rather than controlled burns, are the park's primary maintenance tool. Since the late 1970s, some 300 natural fires have been allowed to burn themselves out. In rare circumstances, natural fires are supplemented by controlled burns that are deliberately started to remove dead timber under conditions which allow fire fighters an opportunity to carefully control where and how much wood fuel is consumed.