26 FOREST REGIONS AND IMPORTANT SPECIES 



the depression between the Central Plateau and the eastern mountains 

 by way of the valleys of the Rh6ne and Sa6ne, traverses the C6te d'Or 

 hills and so gains the valley of the Seine; the other skirting the southern 

 base of the C^vennes, reaches the ocean by way of the Garonne Valley. 

 Another natural highway traversing the lowlands to the west of the 

 Central Plateau unites the Seine basin with that of the Garonne. 



Climate. — The north and northwest of France bear a great resem- 

 blance, both in temperature and produce, to the south of England, rain 

 occurring frequently and the country being consequently suited for 

 pasture. The raias are less frequent in the interior but when they do 

 occur are much heavier, so there is much less difference in the annual raiu- 

 fall there as compared with the rest of the country than in the number of 

 rainy days. The annual rainfall of the whole of France averages about 

 32 inches; the precipitation is greatest along the Atlantic seaboard and in 

 the elevated regions of the interior. It attains over 60 inches in the basin 

 of the Adour (71 inches at the western extremity of the Pyrenees), and 

 nearly as much in the Vosges, Morvan, C^vennes, and parts of the Central 

 Plateau. The zone of level country extending from Rheims and Troyes 



to Angers and Poitiers with the ex- 

 ception of the Loire Valley and the 

 Brie, receives less than 24 inches of 

 rain annually (Paris about 23 inches), 

 as also does the Mediterranean coast 

 west of Marseilles. 



The prevailing winds, mild and 

 humid, are west winds from the At- 

 lantic. Continental climatic influ- 

 ences make themselves felt in the 

 east wind which is frequent in winter 

 and in the east of France, while the 

 Mistral, a violent wind from the 

 northwest, is characteristic of the 

 Fig. 1 (after Jolyet).— The black areas Mediterranean region. The local 

 repr^ent rainfall of over 24 inches the cKmates'' of France may be grouped 

 hatched area 16 to 23 inches, and the dot- , xt. r n • i • 



ted areas 8 to 15 inches. The portions of ^.^^^'' ^'^^ foUowmg seven designa- 

 France left blank represent summer tern- tions: (1) Sequan climate, charac- 

 peratures of over 68° F. terizing the Seine basin and northern 



France, with a mean temperature of 

 50° F., the winters being cold and the summers mild. (2) Breton cli- 

 mate, with a mean temperature of 51° F., the winters being mild and 

 summers temperate; it is characterized by west and southwest winds and 

 2 Based on the six Ecological zones proposed by Dr. Mayr of Munich, the Nancy 

 (Traits Pratique de Sylviculture, 1916, Jolyet, pp. 414-418) school recognizes the fol- 



