42 Peach-Growing 



Other sites suggestive of good local atmospheric drainage 

 are shown in Plate VIII , These orchards are in a valley loca- 

 tion in Colorado where plantings have been made on small 

 mesas at three or four different elevations above the floor 

 of the valley. In the light of the foregoing discussion, it is 

 apparent that frosts might do serious damage in the lower 

 orchards while those on the higher mesas would escape 

 entirely. 



It remains now to state that both topography and eleva- 

 tion in their relation to orchard sites are expressions pri- 

 marily of very local, though often very potent, climatic 

 differences. If an orchard site having a relatively high ele- 

 vation produces more regularly than one with a lower ele- 

 vation, other things being equal, it is because of the local 

 climatic differences which are incident to the different ele- 

 vations. Thus it is that the elevation factor is funda- 

 mentally a climatic factor in its relation to orchards. 



Where the topography is greatly broken, much care and 

 wise discrimination are necessary in selecting orchard sites 

 because of inequalities that may not be apparent on the 

 surface. Sites such as those shown in Plates I and II are likely 

 to have "pockets" into which the cold air will settle, or the 

 soil may vary widely and be unsuited in some places for 

 orchard purposes, or for other reasons the problem of site 

 selection is likely to be more complicated than where the 

 topography is uniform. 



Emphasis has been placed on the importance of relatively 

 high elevations, and in recent years their advantages in com- 

 parison with elevations that are low in relation to surround- 

 ing areas have been repeatedly and unequivocally demon- 

 strated by the frequent frost injuries in orchards situated 

 on the latter in contrast with the infrequent injury where 



