426 FIRE-CONSERVANCY. 



able addition to the area deliberately burnt. And then it must also 

 be borne in mind that whereas we cannot rely on the grass outside 

 the forest being saved, but must even assume that it will certainly 

 burn right up to the boundary traces, we may consider a confla- 

 gration inside the forest as only a contingency that may not occur 

 at all, so that internal traces of a greater width than \vhat would 

 suffice with counterfiring to check the spread of the conflagration 

 would be a superfluity, involving needless expense and needless sac- 

 rifice of a portion of the standing stock. 



So much being said, it may be laid down that the width of a 

 boundary or other trace, the object of which is to effectually arrest 

 the progress of a conflagration, will depend on the height, closeness 

 and inflammability of the grass, the nature, abundance and size 

 of the fallen leaves, the density of the leaf-canopy, the violence and 

 direction of prevailing winds, the intensity of insolation, the slope 

 of the ground, and the dryuess and porous condition of the soil. 

 To these conditions, in the case of traces requiring counterfiring, 

 must be added the rapidity with which fire travels in the forest in 

 question and the promptness with which counterfires can be started 

 and run along them. 



It will thus be seen that the width of a fire-trace is a figure vai*i- 

 able not only from forest to forest, but from locality to locality of one 

 and the same forest. In some places a width of 10 feet may suffice, 

 whereas in others even 600 feet may not prove sufficient in all circum- 

 stances. Hence in each particular case the existing conditions 

 should be fully studied and the width adapted to those conditions. 

 A trace that is not broad enough will defeat the very object for 

 which it was made, while one that is broader than necessary will 

 be a cause of unprofitable expenditure of money and needless sac- 

 rifice of forest growth that ought to be protected. Nevertheless 

 a small margin of safety is always permissible. 



III. Preparation of fire-traces. 



In the preparation of fire-traces the following points have to be 

 considered : (1) width and clearing of the guide lines, (2) 

 necessity or otherwise of clearing the traces of all woody growth, 

 (o) season and time of day for firing and number of times to fire, 

 and (4) the process of firing and how to conduct it. 



7. Guide-lines. 



In preparing a fire-trace the main difficulty is so to control 

 the firing as to prevent the flames from spreading beyond the trace 

 into the areas to be preserved. 



