_Grazing Improvements._ It is often necessary for the complete and economical use of the forage on a National Forest to coöperate with the local stockmen to develop range by constructing improvements. Water may have to be developed; fences, corrals, bridges, trails, and other works may have to be constructed. Often cattle belonging to different stockmen are grazed on adjacent areas which are not separated by natural boundaries such as rivers, ridges, or swamps. If there is no obstacle to prevent the cattle from drifting from one range into another, a drift fence is built, thus definitely separating one stockman's range from the other. Often good range would remain unused on account of lack of water altogether or on account of lack of water during the dry season only. In this case the Forest Service usually coöperates with the stockmen to provide water. Roads, trails, and bridges are often necessary to enable sheep and cattle to reach range lands. _Protective Improvements._ Ranger stations, cabins, lookout stations, firebreaks and similar works are required to protect the forests from fire and are known as protective improvements. Buildings are constructed for the field force to afford necessary shelter and to furnish an office for the efficient transaction of business. Land is often cultivated for the production of forage crops and fences are built to insure necessary pasturage for live stock used by the Forest officers in their work. The buildings may be substantial houses to be used throughout the year or they may be merely such structures as will afford the necessary shelter and domestic conveniences for Forest officers in the summer. These summer camps are constructed where needed for the use of patrolmen, officers engaged in timber sale work or at such points as will serve the needs of officers traveling through the forest. Barns, sheds, and other small structures are constructed at the Ranger's headquarters when they are needed. Office buildings are also constructed for the use of Forest Rangers or for summer headquarters of the Forest Supervisor. [Illustration: Figure 17. A forest fire lookout station on the top of Lassen Peak, elevation 10,400 feet, Lassen National Forest, California. This cabin was first erected complete in a carpenter's shop in Red Bluff, about 50 miles away. It was then taken to pieces and packed to the foot of Lassen Peak. On the last two miles of its journey it was packed piece by piece on forest officers' backs and finally reassembled on the topmost pinnacle of the mountain. Photo by the author.] [Illustration: Figure 18. Forest officers and laborers building a wagon road through trap rock. Payette National Forest, Idaho.]