652 



FUNDAMENTALS OF FRUIT PRODUCTION 



natural or artificial planting sometimes serving admirably as a wind break 

 and protecting the orchard at certain seasons, hinders air movement on 

 calm nights to such an extent that little of the frost protection naturally 

 expected from the orchard's elevation is actually obtained. No rules can 

 be given for dealing effectively with these hindrances to air drainage, but 

 the whole question should be considered on the ground when selecting an 

 orchard site. 



11 II 



24 25 26 Z1 28 23 30 31 . I 2 



December, 1913 Januaa),l914 



Fig. 70. — Minimum temperatures for stations of different elevations during 12 clear, 

 calm, winter nights. (After Batchelor and West'^) 



LOCAL VARIATIONS AND THEIR SIGNIFICANCE 

 Data have been presented showing that points only a few miles apart 

 sometimes, because of topographic pecuharities, present climatic 

 differences great enough to be of considerable importance in fruit growing. 



