DISTKIBUTION OVER THE FOREKT. 



221 



oil the east, so that the cuttings proceed graduahy from east to 

 west. (See diagram. Fig. 48). In this case, the younger age 



Fig. 48. 



classes break the force of the wind gradually, while the youngest 

 (in'the diagram) will gradually grow up exposed to the strong 

 wind ; its edge trees will develop strong root systems, and the 

 wood will then be able to resist the force of the wind, whenj]it 

 grows up to represent the oldest age gradation. 



In determining the prevailing wind direction, it must not 

 be overlooked, that it is frequently changed in hilly and 

 mountainous tracts according to the direction of the valleys 

 and hill ranges. 



Dry winds may frequently blow from a direction differing 

 from that of strong winds; in that case, the forester must 

 decide, which is the more important consideration of the two 

 and determine the'cutting direction accordingly. Frequently 

 the seeds of trees fall under the effect of a dry wdnd, so that 



