Forested areas often contain vast networks of firebreaks. They built roads, ditches, firebreaks, and the residence facilities for the refuge. Natural firebreaks include exposed limestone cliffs and solution sinkholes. Aerial spraying was used to control vegetation along new firebreaks in 1946. They also used "ballistae" for knocking down burning houses and creating firebreaks. In the 14th century Sardinia, firebreaks were used for wildfire protection. Finally, beaver ponds may serve as critical firebreaks in fire-prone areas. The trail travels through frozen swamps, mining areas, and firebreaks for about . Firefighters instead made firebreaks in the roof on September 12 to prevent further spreading. The Pulaski is used for constructing firebreaks, able to both dig soil and chop wood. More realistic city officials had ordered buildings torn down to create long, straight firebreaks. Rubble was often not cleared from the firebreaks, which provided a source of fuel. Since 1976, a network of fire tracks and firebreaks has been created and progressively upgraded. However, the firebreaks were not effective. They also highlighted that the building lacked firebreaks.