238 



FUNDAMENTALS OF FRUIT PRODUCTION 



some of these data are interesting, particularly since, to some extent, 

 they corroborate findings of other investigators. 



In the Early Harvest Apple. — Table 2 is compiled from phenological 

 data gathered by Bailey^ and from daily normal temperatures for the 

 various points, ^^ except that the temperature for Columbia, Mo., is 

 joined with the phenological data for Boonville, a short distance away. 

 Some of the phenological data may be open to question, as, for example, 

 the ripening date for Thomasville, Ga., but even with some allowance for 

 errors, there is apparent a general tendency for temperature summations 

 at southern points to exceed those of more northern location. Though 



Table 2. — Heat Units Calculated on Several Systems Compared with Dates 

 OF Blossoming and of Ripening in the Early Harvest Apple 



relative positions -of certain stations change with different systems of 

 computing the effective temperatures, the same tendency holds through- 

 out and is perhaps most evident with the physiological index summations. 

 If a different zero point — say 50°F. — be assumed, the relative differences 

 are not reduced materially; in fact they are rather intensified, for though 

 northern points would have somewhat lower summation totals, those for 

 Thomasville, Ga., would not be reduced at all, since the normal daily 

 temperature for early January is 50°F. 



In the Elberta Peach. — Gould" reports ripening dates for the Elberta 

 peach at various points in the United States. Certain of these seem near 

 enough to stations for which Bigelow^^ has computed daily normal tem- 

 peratures to make comparisons valid. Table 3 shows summations to the 

 date of ripening and for the year at these points, with the proportion 

 which they bear respectively to each other, Linsser^'^^ has suggested 

 that this ratio should be constant, but the data here presented do not 

 support his suggestion. The same tendency to greater summations in 

 the south than in the north is apparent here. Waugh^''^ found heat units 

 for the blossoming of the "American Wild Plum" in 1898 as follows: 



