ORCHARD LOCATIONS AND SITES 



651 



warding off injury from late spring or early fall frosts. Indeed, there are 

 certain sections in which and certain fruits with which elevation to secure 

 air drainage is of greater importance in dealing with midwinter freezing 

 than with spring frost. The bark and trunk splitting occasionally 



30 



Fig. 





 I9I4 20 



n 



25 24 26 

 November 



27 



?8 



). — The minimum daily temperature for a bench land and a valley bottom 

 station during 9 clear, autumn nights. {After Batchelor and West'^) 



accompanying sudden midwinter drops in temperature in the compara- 

 tively mild climate of the Willamette valley is a case in point. 



Obstructions. — Air drainage is often impeded more or less seriously 

 by obstructions of one kind or another, such as a stone wall, a hedge or a 

 high board fence, a mass or belt of shrubbery. Thus it happens that a 



