276 THE PRINCIPLES OF HANDLING WOODLANDS 



In the north woods the duff is frequently 2 feet deep. 

 A narrow trench, from 1 to 3 feet wide to the mineral 

 soil, suffices to stop or check a ground fire. The trees 

 and brush are cleared for a width of 6 to 15 feet, to facili- 

 tate work in fighting fire and in constructing and main- 

 taining the trench. 



Fully cleared fire-lines should be cleaned off every 

 year or two. The leaves and other debris accumulating 

 upon them should be removed by burning or otherwise, 

 and in the case of grubbed lines the soil should be stirred 

 over by raking or harrowing. 



The work of burning over the fire-line can best be 

 done in early spring. The leaves and other debris will 

 become dry on the open fire-line sooner than in the 

 adjoining forest or chaparral. The aim should be to do 

 the burning at exactly the time when there will be the 

 least danger of the fire spreading to the woods. It is, 

 however, not always possible to organize the crew so as 

 to have the work done at the most favorable period. In 

 the case of an extensive tract the work may be begun 

 exactly on time, but the whole woods may become dan- 

 gerously dry before it can be finished. It is especially 

 difficult to carry out this work of burning over the fire- 

 line in open pine woods on dry, sandy soil. 



When the burning has to be deferred until the woods 

 as well as the fire- line are dry, great care should be exer- 

 cised in the work. If the ground cover consists of leaves 

 or needles, the procedure is as follows: 



Narrow, cleared traces are made on each side of the 



