THE PROTECTION OF FORESTS FROM FIRE 



By HENRY S. GRAVES 

 Forester, United States Department of Agriculture 



fart II'- Continued from November Xuinber 



Cleared fire lines are also used in ex- 

 tensive pine forests on dry, sandy land. 

 Fires start easily and run swiftly under 

 such conditions, and fire lines are easy 

 to construct and comparatively cheap 

 to maintain. Thus, in the pine forests 

 of northern Germany and southern 

 France, wide cleared lines are used to 

 supplement the road systems. 



The danger from fire is always very 

 great in the regions of the Tropics that 

 have a pronounced dry season. In In- 

 dia, for example, fire protection con- 

 stitutes one of the greatest problems of 

 management. The forest becomes very 

 dry in the hot season, and there is a 

 great abundance of grass, which ignites 

 readily and carries fire swiftly. Under 

 these conditions cleared fire lines are 

 absolutely necessary for efficient protec- 

 tion. 



The width of fire lines varies greatly 

 under different conditions. In general 

 the following classes from the stand- 

 point of width may be recognized : Nor- 

 mal, from 6 to 15 feet; wide, from 15 

 to 30 feet ; very w r ide, from 30 to 60 

 feet. In Europe fire lines are usually 

 about 10 to 15 feet wide, but in the pine 

 plains they are often as wide as 50 feet. 



In this country such fire lines as have 

 been constructed are usually less than 

 one rod in width. In the chaparral of 

 California, however, broad lines from 

 40 to 60 feet wide have given the best 

 results in stopping fires. 



It is seldom necessary or practicable 

 to make fire lines over 60 feet wdde. 

 Usually it is more economical to make 

 a number of narrow lines rather than 

 a few very broad ones. 



In constructing a fully cleared fire 

 line the timber and brush should all be 



710 



removed or disposed of to the desired 

 width. Where it is impossible to util- 

 ize the timber, the logs may be left 

 along the side of the lines. The brush 

 and other debris should be burned. 

 Piling the brush along the edge of the 

 line is a dangerous practice. As a rule, 

 the best plan is to burn the brush in 

 piles in the cleared area, and then burn 

 the ground litter by a broadcast fire. 



In the best permanent lines the 

 stumps are all grubbed out and the soil 

 is occasionally stirred by grubbing or 

 harrowing. Sometimes only a part of 

 the line is cleared to the soil. Thus, 

 for example, the timber and brush may 

 be cleared from a strip from 10 to 15 

 feet wide, and a narrow strip or trace 

 about four feet wide ground-cleared. 

 This cleared trace may be located in the 

 middle of the line, or on one side. A 

 good plan is to make two traces, one on 

 each side of the fire line. The advan- 

 tage of the last plan is that it affords 

 a very good protection when burning 

 the debris on the line. 



The method of constructing a nar- 

 row, ground-cleared trace, covering 

 only a part of the fire line, is very com- 

 monly used where there is a deep duff 

 on the ground. It is then a question 

 of protection against ground fires. Un- 

 der such circumstances the trace is 

 usually a trench. In the north woods 

 the duff is frequently two feet deep. A 

 narro\v trench, from one to three feet 

 wide to the mineral soil, suffices to stop 

 or check a ground fire. The trees and 

 brush are cleared for a width of from 

 six to 15 feet, to facilitate work in 

 fighting fire and in constructing and 

 maintaining the trench. 



