Orchard-Heating 



271 



more the orchard -heaters are massed in the form of a 

 square, the better the results. In fact, it is almost impos- 

 sible to protect an orchard of only a few rows because 

 there is no massing of the heat generated on account of 

 the lack of braking effect on air-movement." Figs. 96, 97, 

 98 (from Standard Cyclo. Hort.) show some of the methods 

 in orchard-heating. 



Experiments in Indiana (Bull. No. 154) lead Wood- 

 berry and Wellington to conclude that "Whether or not 

 orchard-heating pays depends on whether spring frost- 

 injury is the limiting factor in the production of the crop. 

 There are probably some orchards on sites of such a 

 nature, and cared for so well in every other respect, that 

 spring frost-injury is the limiting factor in crop-produc- 

 tion. In these orchards, heating would be profitable. 



FIG. 97. Protecting the windward side of an orchard by using a double row of 



oil-heaters. 



