284 THE PRINCIPLES OF HANDLING WOODLANDS 



roads, the location is governed largely by the principles 

 of road construction. Special fire-lines, however, con- 

 structed for protection alone, are built mainly on the 

 crest of ridges. (Fig. 60.) For example, the wide lines 

 in southern California, already mentioned, are on the va- 

 rious ridges. A fire runs up a slope very rapidly and 

 works . over a ridge slowly. If there is a wide, cleared 

 fire-line on the ridge the fire may be stopped entirely by 

 it alone. In the southern Appalachians and other moun- 

 tains, the old mountain trails on the ridges may be devel- 

 oped into admirable fire-lines. 



The question of when and where to construct special 

 fire-lines must depend on local conditions, the danger 

 from fire, the value of the forest, the organization of 

 patrol and force available for fighting fire, the object 

 of the owner in protecting the forest, and many other 

 factors. As with other operations of management, the 

 expense must be justified by the results which their con- 

 struction is intended to accomplish. 



Artificial Fire Obstructions. It is well known that 

 a small, creeping surface fire is stopped or checked by a 

 stone wall or other similar obstruction. This principle 

 may be used in fire protection, and other types of fire- 

 lines may often be dispensed with where there are such 

 obstructions. A well-known railroad has been experi- 

 menting with a specially constructed fire-wall. 



Supervision and Patrol. A careful supervision or 

 patrol during the dry season is one of the most important 

 measures in organized forest protection. Its purposes 



