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PLANT SOCIOLOGY 



beech region of central Switzerland. Long stretches of the famous 

 Mediterranean Macchia are nothing but high forest which has been 

 permitted to degenerate in this manner into dwarf or low woods, 

 where formerly Q. ilex dominated (Fig. 147). In the excessively- 

 deforested Islamic lands the graves of saints (Marabouts) are refuges 

 for the original vegetation, since trees in the immediate vicinity enjoy 

 the protection of the faithful. 



The secondary tropical "virgin" forest owes its origin to complete 

 cutting followed by fires. If the surfaces are left to themselves, even 



Fig. 147. — Quercais coccifera scrub Ueltj; sclerophyll macchia due to 20 years of 

 cutting on right; center, large Quercus ilex, a remnant of the former climax forest, valley 

 of the Vistre, southern France. {Photo by P. Keller and Braun-Blanquet.) 



for ten years, the secondary virgin forest appears with a 25-m.-high 

 tree layer of soft woods and impenetrable undergrowth. The hard 

 woods of the primary virgin forest, on the other hand, appear much 

 later, and centuries may pass before the original tropical climax forest 

 comes into its own once more (Chevalier, 1925; Perrier de la Bathie, 

 1921;Benoist, 1923). 



Mowing, Fertilization, Irrigation, Reclamation. — With the use of 

 sickle and scythe in the bronze and iron ages we see the beginnings 

 of the cultivation of food plants, the extension of cultivated and 

 semicultivated land. Mowing has about the same effect upon the 



