28 TUNISIA 



But if this method of protection is effective it is on the 

 other hand very expensive. It should only be applied to 

 fully stocked forested areas which can compensate by their 

 revenue for the outlay. For the rest of the stands one can 

 only make use of fire lines laid out on the main ridges and 

 dividing the forest in blocks of varying size according to the 

 ground. But these Hnes must be at least 50 metres (55 

 yards) wide, must be entirely cleared of every tree, stem 

 bush, shrub, etc., and have in the center an area 10 to 15 

 metres (11 to 16 yards) wide where all stumps have been 

 removed on which can be built either a good path or a cause- 

 way of stones according to the quahty and configuration .of 

 the soil." 



Problems in Protection. — The main problems in protection 

 which have confronted the forest administration in the cork- 

 oak forests are as follows: (i) How to secure successful pro- 



Fig. 6. — A recently cleared fire line in cork oak. 



tection; (2) value, need, and cost of fire lines; (3) their location, 

 width, clearance, maintenance, and the execution of the work 

 by contract. 



Fire Lines. — With the inflammable underbrush uncleared 

 on the forest as a whole, successful protection can be assured 

 only by the periodical brush removal on the fire lines, which is 

 usually done on a cycle of three years. 



