EFFECTS OF FREEZES ON CITRUS IN CALIFORNIA 



273 



as high as 50 cents a tree in removing this oiled soil from their groves 

 after the freeze. 



One conclusion very definitely reached by growers, largely from 

 the results obtained in this freeze, is that in the heating of an orchard 

 it is stoves radiating actual heat that is needed, and not those pro- 

 ducing a smudge. The smoke given off by the oil heaters collects to 

 some extent on the fruit and is difficult to remove. 



Fig. 9. Lighting a good recent type of orchard heater by means of a 

 torch containing distillate. The fire being applied to a small amount of 

 excelsior placed in the tube of the down draft. The cover on the right when 

 placed on the heater, extinguishes the fire and excludes rain. Photo by 

 Barrett. 



Methods. The groves in which the best work was done Avere 

 equipped with one pot to the tree. These burned approximately 100 

 gallons an hour per acre, when they were all going full blast. At 

 these times the temperature of the grove was often from 8 to 12 

 degrees higher than the temperatures in neighboring unheated groves. 

 Of course it was only during the coldest weather that it was necessary 

 to have all the pots burning at full capacity. Usually only one-fourth 

 or one-half of the pots were lighted, and after these had burned a 

 time they were extinguished and another portion lighted, so that 



