The Bulletin. 9 



in the Kocky Mountains I saw one of these small valleys shut in by 

 hills, in which all the vegetation was nipped by frost. The surround- 

 ing hills on one side were somewhat lower than on the other sides. 

 When the valley became full of cold air it flowed over the lowest side, 

 just as water would have done. All around on the other sides of the 

 valley the high frost mark could be seen, and it formed a line on a 

 level with the top of the lowest hill where the frosty air had flowed 

 over. Above this line the tenderest vegetation showed not the slightest 

 injury. A valley with a large outlet will usually be reasonably safe 

 from frost. The land about rivers which have a considerable fall will 

 be drained of water and also of cold air. Lands contiguous to such 

 streams can be counted on as being reasonably safe from frost. Expe- 

 rience with frost shows that mountain regions are much safer for fruit 

 growing than the lower lands below them. 



A carefully planned and conducted experiment which I made two 

 years ago in a hillside peach orchard confirms the results of general 

 experience on this point. This orchard was carefully surveyed with a 

 leveling instrument and the ground mapped out in contours. Contour 

 lines connected all trees at the same elevation. There was two_ feet 

 difference in elevation between each two contour lines. Self -register- 

 ing thermometers were placed on each contour line and readings were 

 made on them three times a day throughout the entire winter and 

 spring. The lower contour lines almost invariably registered lower 

 temperatures than the higher ones. There was usually from one-half 

 to one degree of difference between each line and the one above it. 

 Instruments placed along one contour line, thus all being at the same 

 elevation, showed practically no difference in temperature. During 

 the winter zero temperatures were recorded in this orchard. At 

 pruning time in the spring it was found that the wood of the trees on 

 the lowest contour had been badly frozen and was "black-hearted." 

 The effect of the "black-hearting" lessened with higher contours, and 

 on the highest one not a single affected tree could be found. The 

 only fruit produced in the orchard was on the two highest contours. 

 Higher land above this, which was not planted in orchard, would un- 

 doubtedly have been a safer location for peaches. The same season 

 an estimate was made on the effect of winter freezing of peach buds 

 on trees grown on comparatively level land. A measuring pole was 

 placed in the trees and by means of a step-ladder the buds were ex- 

 amined and counted at different heights from the ground. An exami- 

 nation of 1,300 buds gave the following percentage of buds killed by 

 frost : 



Two feet from the ground 50 per cent. 



Four feet from the ground 30 per cent. 



Eight feet from the ground 16 per cent. 



These are only a few of hundreds of such examples that could be 

 given to show the advantages of elevated locations for fruit growing. 



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