30 TUNISIA 



for a secondary line and 120 (131 yards) for an important di- 

 vision fire line. Along railroad rights-of-way the prescribed 

 width is 20 metres (22 yards) from the track. This belt must 

 be kept cleared of brush and all coniferous trees. 



Clearance. Whether to merely cut the brush, or to grub it 

 out by the roots; whether to fell all trees on the line or only 

 a portion; and how often to clear lines, are among the problems 

 of clearing. In actual practice most of the lines are merely 

 brushed and healthy oaks usually are not felled when they are 

 producing cork in merchantable quantities; but as cork-oak 

 trees become overmature they are cut clean with the ground, 

 so that on most fire lines there is now rather a scattering growth 

 which, in the process of time, will gradually disappear and give 

 way to completely cleared lines. In zeen oak, however, the 

 lines are often kept dense, since this species keeps weeds and 

 underbrush shaded out. No coniferous species are left on fire 

 lines. 



All lines are cleared every three years and the work is so 

 arranged that the trail and road maintenance can usually be 

 accomplished under the same contract. This arrangement is 

 not altogether satisfactory, because of the rapid growth of the 

 brush and weeds. After one season this new growth seriously 

 impairs the value of the line; the third year it is badly in need 

 of clearing. To clean every year or every other year would 

 entail too great an expense, so that a compromise is made with 

 three-year intervals between brushings. Under present con- 

 ditions it is usually necessary to clear a line of defense along 

 the fire line in case of an approaching fire, since the fire would 

 otherwise cross. 



Theoretically, at least, a better policy would be to annually 

 clear ^ say, one-third of the line along its entire length, so that 

 there would always be an area free from weeds and brush 

 to serve in case of back firing, or as a means to stop a light 

 ground fire from crossing. The main objections raised to this 

 plan was the impracticability of narrow lines, because of the 



11 This scheme has never been tried out, but was suggested by Forest Assist- 

 ant Charvet at Feidja. 



