GENERAL ADMINISTRATION AND PROTECTION. 65 



ients, sources of supply for labor, equipment, food, and forage; and location of 

 imping grounds, lookout stations, and firebreaks. 



;ial Protective Surveys. 



On those Forests which have an extremely high liability, and of which the 

 exist ing maps are very inaccurate, the project of a protective survey should be 

 considered. Such a survey should aim to produce merely an accurate topo- 

 graphic map with a delineation of the types of cover and a rough estimate of 

 the timber. Ordinarily a survey should not be undertaken for this purpose 

 alone if its cost will exceed 1 cent per acre. 



Statistical Information. 



The fire-protection map should be supplemented by statistics by ranger dis- 

 tricts, giving an appraisal of the liability, the degree of hazard, and the liability 

 insurance (or the amount of money which may properly be expended for fire 

 protection) based on the value of the property to be protected. 



THE FIRE LIABILITY. 



The amount of money which may properly be expended on protection nat- 

 urally is determined by the amount of damage which fire may inflict, and this 

 damage is, in turn, dependent on the character and value of the forest cover. 

 Therefore the fire liability of each type of forest should be determined as accu- 

 rately as possible by means of a study of the results of previous fires. Damage 

 may include the actual loss of merchantable or potentially merchantable timber ; 

 of forage; of protective value; or in the reduction of the productiveness of the 

 land. Ordinarily, the liability should be expressed definitely in terms of money. 



Reduction of Liability. 



The study of the fire liability should include the determination of the location 

 and amount of merchantable timber in burns, or in isolated bodies, which are 

 so situated that successful protection is practically out of the question. The 

 sale of such bodies of timber should be carefully considered. 



THE FIRE HAZARD. 



The fire hazard depends upon the inflammability of the forest cover and upon 

 the degree to which it is subject to the chance of ignition. The hazard of dif- 

 ferent types of forest can be measured only in terms of relative risk, such as 

 high, moderate, and low. The determination of this risk will involve a study 

 of the history of fires on the Forests, with particular reference to their causes 

 and frequency and to the forest's inflammability. 



Reduction of Hazard. 



Measures to reduce the fire hazard will include the grazing of areas not now 

 grazed, the removal of combustible material from camping sites and other 

 areas of great hazard, the burning of slashings or old burns at safe seasons, 

 the use of oil as fuel and of spark arresters on locomotives and other engines, 

 and the adoption of silvical methods which will help to keep the forest free 

 of combustible material. 



PREVENTION AND CONTROL. 



The methods and the cost and difficulty of extinguishing a fire varies not only 

 with the type of cover, but with the kind of fire. Thus in regions where fires 

 are easy to extinguish and do but little damage there will be required protective 

 measures which will differ from those for forests which are subject to complete 

 destruction and in which fires are extremely difficult to control. A careful 

 study must therefore be made of the relative cost and difficulties of fire control 

 in the different types of forest. 



Transportation and Communication. 



The costs and difficulties of prevention and control will depend also upon 

 means of transportation and communication. An adequate system of roads and 

 trails and means of communication between lookouts, patrol stations, and the 

 headquarters of rangers and the supervisor is of utmost importance. 



These subjects are treated in detail in the Improvement section of the Manual. 



Firebreaks. 



Firebreaks greatly reduce the hazard and the cost of prevention and con- 

 trol. Their absolute value is not as yet wholly determined for the United 



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