432 FIUE-CONSERVANCY. 



if ever, be possible to do away with the necessity of a second, 

 third, and even fourth firing. "When, however, a cleared line of 

 sufficient width already exists defining the boundary of the forest, 

 the necessary trace is there ready to hand, and then the charge for 

 clearing it is of course not one that is debitable to fire-conservancy. 

 In discussing the present question it is a mistake to suppose, as 

 is so often done, that cleared traces escape being covered over with 

 a deposit of dead leaves and that they thus save the trouble and 

 expense of having to sweep away this highly inflammable stuff 

 during the season of leaf-fall. Leaves shed by bordering trees are 

 always wafted on over the trace in sufSoient abundance to make it 

 dangerous. 



S. — Season fov firing tlie traces and the numher af times to fire them. 



A trace can be completely cleared in a single firing only under 

 one of two conditions ; either the grass on it should everywhere be 

 dry, or, if it is not all quite dry, a steady breeze should be blowing 

 during the firing operation to cause the combustion of the still 

 riioist portions. Now we know that the simultaneous drying up of 

 the grass on any considerable length of trace is a rare, if not an 

 impossible, occurrence, while such a wind as is necessary to assure 

 the combustion of grass that is not uniformly dry and is yet not 

 too strong for the safe conduct of the firing, cannot be expected 

 to blow at our pleasure. To wait until all the grass on the fire- 

 traces became combustible would mean the daily and even 

 momentary risk of an outside conflagration entering the forest by 

 way of the portions already dry. Indeed such waiting would 

 mean even more than this, for by the time the grass on the traces 

 had everywhere become dry enough to bum, that on the preserved 

 area would also have become inflammable, so that there would 

 always be the danger, if the fire on the burning trace got out of 

 control, of its spreading away unchecked into the forest. Hence 

 a safe rule to follow in practice is to commence firing a trace as 

 soon as there is enough dry grass on it to enable it to bum in a 

 more or less continuous manner ; whatever grass remains unburnt 

 must be got rid of by a second, and, if found necessary, also a 

 third and even a fourth firing. These subsequent firings need not 

 cause any alarm on the score of expense, for they must in any 

 case be undertaken in order to clear the traces of dead fallen 

 leaves. 



It is obvious that different considerations determine the time for 

 firing boundary and internal traces, for the former must be made 



