270 



FUNDAMENTALS OF FRUIT PRODUCTION 



of soft, poorly matured wood, or in orchards in rich soils, receiving late 

 cultivation."^^ Emerson^^ found similar susceptibility in peaches grow- 

 ing in rather moist soils or receiving late cultivation in Nebraska. Zero 

 weather or even 6°F. above is considered more harmful in very early 

 winter in Montana than -30°F. or -40°F. later.e^ 



Selby^^^ supplies other interesting cases of injury in Ohio associated 

 with immaturity. In 1880-1881, late cultivation in two orchards, 

 accompanied by heavy August rainfall and normal September rainfall, 

 produced heavy and prolonged growth. Late November brought zero 

 weather; the December minimum was -13°F. These temperatures 

 ordinarily are of no great significance but in this case they caused complete 

 destruction of Baldwin apple trees. On a larger scale and over a wider 

 area, the same climatic conditions, when approximated in the growing sea- 

 son of 1906, were followed by widespread winter injury. In this case the 

 following winter was severe but, as is shown in Table 19, arranged from 

 Selby's data, in no month of this winter did the temperature closely 

 approach recorded minima. It was definitely established that much of 

 the injury was done by a temperature of + 18°F. on Oct. 12. The 

 unusual features of these two damaging years were, not the winter 

 temperatures, but the summer and fall temperatures and rainfall. 



"Second Growth" Particularly Susceptible. — Excessively dry summer 

 weather also, if followed by a fair precipitation in early autumn, may 

 result in immature wood at the entrance into winter. ^^^ The dry sum- 

 mer may cause a "premature dormancy" followed by second growth. 



