58 The Principles of Fruit-growing 



patches of wild berries. It is not often, however, that the 

 forest areas become a very serious menace to fruit-growers. 



General statement. — The advantages derived from 

 windbreaks are many, positive, and they appear to warrant 

 the strongest recommendations of horticultural writers. 

 Yet the injuries occasionally sustained in consequence of 

 shelter-belts may be serious, for it is well attested that 

 trees sometimes suffer from cold in the immediate vicinity 

 of a dense windbreak when they escape injury in other 

 places. This fact is easily explained, however. The influ- 

 ence of a windbreak on the temperatures of an adjacent 

 plantation is governed by its position with reference to 

 prevailing or severe winds. Of itself, wind probably exerts 

 little or no influence on temperature. It acquires the 

 temperature of surfaces over which it passes. If these 

 surfaces are colder than the given area, cold winds are the 

 result, or if warmer, as a large body of water, the winds are 

 warm. But wind often causes great injury to plants 

 because of its acceleration of evaporation; and winds that 

 are no colder than the given area, if comparatively dry, 

 may consequently do great damage to fruit-plantations. 

 This is particularly true at certain times in the winter 

 season. Land winds, being cold and dry, are at that time 

 likely to be dangerous; whereas winds that traverse large 

 bodies of water, and are therefore comparatively warm 

 and moist, are usually in themselves protectors of tender 

 plants. 



The advantage or disadvantage of the windbreak, 

 therefore, depends directly on the configuration or topog- 

 raphy of the particular place, and the problem is strictly 

 local. But it may be said that a windbreak is desirable 

 wherever the fruit-plantation is much exposed to strong 

 winds. To prevent possible injury from too little circu- 



