TREES AS SHELTER TO GROUND TO THE LEEWARD. 165 
The local retardation of spring, so much complained of in 
Italy, France, and Switzerland, and the increased frequency of 
late frosts at that season, appear to be ascribable to the admmis- 
sion of cold blasts to the surface, by the felling of the forests 
which formerly both screened it as by a wall, and communi- 
cated the warmth of their soil to the air and earth to the leeward. 
Caimi states that since the cutting down of the woods of the 
Apennines, the cold winds destroy or stunt the vegetation, 
and that, in consequence of “the usurpation of winter on the 
domain of spring,” the district of Mugello has lost all its mul- 
berries, except the few which find in the lee of buildings a pro- 
tection like that once furnished by the forest.* 
The department of Ardéche, which now contains not a single 
considerable wood, has experienced within thirty years a climatic 
disturbance, of which the late frosts, formerly unknown in the 
country, are one of the most melancholy effects. Similar results 
have been observed in the plain of Alsace, in consequence of 
the denudation of several of the crests of the Vosges. 
Dussard, as quoted by Ribbe,t maintains that even the 
in the Revue des Deux Mondes, I find this statement: ‘‘ A spectator, placed on 
the famous bell-tower of the cathedral of Auiwerp, saw, not long since, on the 
opposite side of the Schelde, only a vast desert plain; now he sees a forest, 
the limits of which are confounded with the horizon. Let him enter within 
its shade. The supposed forest is but a system of regular rows of trees, the 
oldest of which is not forty years of age. These plantations have ameliorated 
the climate which had doomed to sterility the soil where they are planted. 
While the tempest is violently agitating their tops, the air a little below is 
still, and sands far more barren than the plateau of La Hague have been trans- 
formed, under their protection, into fertile fields.”—Revue des Deua Mondes, 
January, 1859, p. 277. 
* Cenni sulla Importanza é Coltura dei Boschi, p. 31. 
+ CLAVE, Etudes, p. 44. 
Tt has been observed in Sweden that the spring, in many districts where the 
forests have been cleared off, now comes on a fortnight later than in the last 
century.—ASBJORNSEN, Om Skovene t Norge, p. 101. 
¢ La Provence au point de vue des Torrents et des Inondations, p. 19. 
Dussard is doubtless historically inaccurate in making the origin of the 
mistral so late as the time of Augustus. Diodorus Siculus, who was a con- 
temporary of Julius Cesar, describes the north-west winds in Gaul ag 
