10 



caused in this manner. Statistics compiled lay the For- 

 est Service in California show that the number of fir^ 

 caused "by lightning between 1908-1918 is 35^ of "the to- 

 tal number occurring on the National Forests. It must 

 be borne in mind that fires caused by lightning are in 

 a great many cases among the higher bold, rocky peaJts 

 where the timber is often practically inaccessible and 

 of poor quality. It has been found that lightning 

 storms are extremely common in certain of the higher 

 Sierra, regions or in what are termed "lightning zones". 

 In many cases electric storms occur without any accom- 

 panying precipitation. These "dry" lightning storms 

 may in some cases cause enormous damage by setting 

 fires scattered about over large areas. Thus, on June 

 12, 1918, a severe "dry" lightning storm started 1^0 

 fires within the state. Hence, due to frequent elec- 

 tric storms during the dry season, we may conclude 

 that fires can never be entirely eliminated from the 

 California forests. 



Fires occurring as the result of human activities 

 are the greatest source of forest destruction, Man in 

 his daily pursuits, many of which require the use of 

 fire, is a continual source of danger. Consequently, 

 fires result from the use of fire by railroads and in 

 brushburning, by lumbering, thru the carelessness of 

 campers and hunters, by incendiarism, and due to mis- 

 cellaneous and unknown causes, making in all, approx- 

 imately 65^ of the total number of fires occurring. 



