Note 16 — FROM LAGHOUAT TO GHARDAIA.

Massart, loc. cit., p. 314, suggests that the Sahara may be gradually becoming more arid and says that as a result the betoum is becoming more and more rare and may become extinct. He says “L’extinction du Pistacia atlantica présente le caractère, tout à fait exceptionnel, d’ètre uniquement l’effet du climat.” It will appear from what is said in this study regarding the effects of grazing in general, as well as the especial effects on the betoum, that if the betoum is becoming extinct the sole cause, or perhaps the main cause, is not the adverse climate.