GROWING SEASON TEMPERATURES 



245 



As Schimpei-i^i points out, the forcing of fruit under glass is merely a 

 shortening of the dormant season and the period of maturity is advanced 

 only as much as the inception of growth precedes that in the open. The 

 temperatures found best for the trees indoors are those they receive at 

 corresponding stages out of doors in favorable regions; higher temperatures 

 are not beneficial. 



Price 1^^ reports investigations showing certain temperatures more 

 favorable to the opening of fruit buds than others. With branches of 

 various fruit trees in incubators maintained at different temperatures he 

 found progressive acceleration in the opening of the buds with the higher 

 temperatures. Some of the data he reports are used in compiling Table 8. 



Table S. — Influence of Temperature on Opening of Fruit Buds 



Fruit 



Date of 

 beginning 



Davs to full bloom 



70°F. 



79°F. 



88°F. 



Abundance plum. . . 



Hale plum 



Luster peach 



Kieff er pear 



Oldenburg apple 



Rome Beauty apple 



Jan. 28, 1908 

 Dec. 3, 1909 

 Feb. 2, 1909 

 Mar. 7, 1910 

 Apr. 1, 1909 

 Apr. 22, 1909 



Tufts''^ reports interesting indications that very high temperatures may 

 retard the ripening of fruit. "Here," he states, referring to the Winters section 

 in the Sacramento valley, "... the apricot ripens some two or three weeks prior 

 to the ripening of the apricot crop in the Santa Clara Valley, although apricot 

 trees in the Santa Clara Valley bloom ten days earUer than they do in the Winters 

 section. Undoubtedly the nearness of the ocean and the influence of the San 

 Francisco Bay profoundly modify the climate of the Santa Clara Valley. The 

 Apricot crop in the Winters section is entirely harvested by July 1. 



"When it comes time for the prune harvest, however, we find that the Santa 

 Clara Valley is generally pretty well along — about half way through — before the 

 prunes in the Sacramento Valley are ready. The only explanation we have for 

 this apparent inconsistency is the fact that probably the temperatures for the 

 ripening of the apricot crop are optimum in the Winters section. However, after 

 the first of July the weather gets excessively warm, with the result that the prunes 

 are retarded in their development, and the optimum temperatures for the develop- 

 ment of the prune crop probably exist in the Santa Clara Valley during the latter 

 part of the growing season." 



Schimper/^" emphasizing that different functions require different 

 temperatures, states: "the oecological optimum temperature does not 

 remain constant during the whole development of a plant, at least in tem- 



