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CHAPTER III. 



PROTECTION AGAINST WINDS. 



WINDS may be classified in various ways, by their speed, as 

 winds and storms ; tbeir origin land- or sea- winds ; their 

 direction according to the point of the compass from which 

 they blow ; the damage they inflict on forests, by drying up 

 the soil, impeding height-growth and the formation of a 

 regularly-shaped crown in trees, or by breaking and over- 

 throwing individual stems or whole woods, the last injury 

 being caused only by storms. 



Wind, by blowing caterpillars from older trees on to young 

 growth, may also increase the damage done by insects ; this 

 has been observed frequently in the case of attacks by the nun 

 moth. Winds also spread the spores of fungi. 



SECTION I. PREVALENT WINDS. 



South-westerly winds are most prevalent in Central Europe, 

 especially during autumn and early winter. They blow as 

 cool winds during summer, and are comparatively warm in 

 winter, and bring much moisture and rain-clouds from the 

 ocean. Dry winds from the north-east and east prevail 

 generally during the spring, the cutting north-east wind on the 

 coasts of the Adriatic being termed bora. The well-known 

 cold north-east wind, named mistral, blows down the Eh one 

 Valley, in France, and in Switzerland a hot dry wind from 

 the south frequently prevails during the summer months and 

 is termed fohn. Cold winds from mountains down on to valleys 

 and plains blow generally at night, forming air -cataracts. 



1. Damage done. 

 A. General Account. 



Prevalent winds dry up and disperse the soil-covering, 

 blowing dead leaves from slopes and ridges, and heaping 

 Ibhem uselessly in hollows ; they hinder the formation of dew, 



