142 PRINCIPLES OF PLANT CULTURE 



The premature blowing off of fruits may be in a measure 

 prevented by planting fruit trees where they are more or 

 less sheltered from prevailing winds by shade trees, 

 buildings, forests or elevations of land. Orchards may 

 be in part protected by planting a windbreak on the wind- 

 ward side (203). 



Shade trees in exposed situations should be headed 

 low, and the head should be formed of numerous branches. 

 The higher the head, the more it is exposed to wind and 

 the greater is the leverage upon the trunk. Several small 

 branches are better able to bear the tempest than a few 

 larger ones. 



Shade trees for exposed situations should be of 

 species not likely to be deformed by wind. Certain 

 trees, as the white maple (Acer saccharinum) , often 

 develop one-sided if planted where exposed to prevail- 

 ing winds, while others, as the sugar maple (Acer sac- 

 charum) and Norway maple (Acer platanoides) , are 

 not thus affected. 



PLANTS AS AFFECTED BY INSUFFICIENT WIND 



245. Fungous attacks. Insufficient wind promotes 

 the development of certain fungous parasites (-821) by 

 favoring an excessively moist atmosphere. Orchards 

 too closely planted or surrounded by wind barriers suffer 

 more from fungous attacks than those having freer cir- 

 culation of air between the trees. 



246. Frost damage. Insufficient wind promotes dam- 

 age from frost by permitting cold air to settle in the lower 

 places (209). On these accounts, gardens and fruit 

 plantations should not be entirely surrounded by wind 

 barriers. 



