4 86 



Yearbook^ of Agriculture 1949 



diarists, smokers, and debris burners. 

 Lightning is a major problem on the 

 more mountainous national forests, 

 but it is not so important a factor in 

 private fire-control management ex- 

 cept in a few localities. 



Complete exclusion of forest fires is 

 rarely attainable. The degree of pro- 

 tection that is necessary depends on the 

 purposes of management and the dam- 

 age that fires may be expected to cause 

 in a given area. A theoretical guide is 

 that it is desirable to keep the total an- 

 nual cost for all fire-control measures 

 plus annual fire losses to a minimum 

 figure. In other words, the economic 

 objective is to secure adequate protec- 

 tion at least cost. The problem is the 

 same for State, county, municipal, and 

 Federal agencies, and the index of jus- 

 tifiable protection the goal of "least 

 cost plus damage" might also apply 

 to private protection agencies even 

 though they are answerable to a board 

 of directors rather than to the public. 



EFFECTIVE FIRE CONTROL requires a 

 careful analysis of all important factors 

 related to the fire problem and the 

 preparation of specific action plans for 

 each major part of the protection job. 



The completed plans in combination 

 are termed "presuppression plans." 

 Their primary objective is a fire-con- 

 trol organization that is capable and 

 well-trained, adequately equipped, and 

 properly supervised one that will re- 

 duce the number of man-caused fires 

 and can handle the worst fire situation 

 that is likely to arise. 



The elements in the planning are : 



1. The major causes of fires and the 

 measures needed to prevent or reduce 

 those that are man-caused. 



2. Occurrence of fires past occur- 

 rence and location, segregated by ma- 

 jor causes, seasonal periods, and times 

 of day. 



3. Fuels kinds, density, and their 

 relative inflammability and resistance 

 to control measures. 



4. Topography whether flat, roll- 

 ing, or rough ; steepness of slopes ; and 

 other features affecting fire behavior. 



5. Accessibility relative difficulty 

 in reaching a fire with suppression 

 forces and the additional facilities 

 needed with transportation available. 



6. Visibility distance in miles a fire 

 observer may normally be expected to 

 see an incipient fire. For example, in 

 the usually clear atmosphere of the 

 West, a small fire 15 miles away can be 

 readily detected, but in the Coastal 

 Plains of the Southeast the visibility 

 distance is about 6 miles. 



7. Meteorological factors : the wind, 

 temperature, relative humidity, dryness 

 of fuels, precipitation, thunderstorm 

 activity, length of fire seasons, and the 

 like. 



8. Production in fire-control meas- 

 ures per unit of manpower or machine. 



Besides these basic factual surveys, 

 consideration needs to be given to other 

 features more closely related to the 

 operational phases of the protection 

 plan. These we shall mention later. 



The significance and effects of all 

 pertinent factors must be correlated 

 and definite conclusions must be 

 reached and reflected in a "master" 

 presuppression plan. The master plan 

 is really not a single document; it is a 

 term applied to the coordinated prepa- 

 ration and use of a number or series of 

 specific plans that cover each major 

 phase of action. 



Different methods have been devel- 

 oped and used to prepare presuppres- 

 sion plans, but nearly all have the same 

 objectives and fundamental factors. A 

 good way to depict a plan of the usual 

 type is to assume that we have the task 

 of preparing one for an area of several 

 million acres a typical tract that con- 

 sists of wild, remote, rugged forest 

 lands on which fires have been bad and 

 losses high. 



THE BEST POINT AT WHICH TO BE- 

 GIN is with the precept that the best 

 fire control is to prevent fires from 

 starting. Nine of every ten forest fires 

 in the United States result from man's 

 carelessness in his use of fire; all of 

 them can be prevented. Our major ob- 

 jectives, then, are: 



