CLIMATOLOGY 25 



whitewash treatment with the spring application of 

 lime-sulphur so essential in fighting the San Jose 

 scale. 



SMUDGING 



There has long been a theory among fruit grow- 

 ers that orchards could be protected from late spring 

 frosts by the use of smudges. The principle on 

 which this treatment rests is that a heavy blanket of 

 smoke lying over an orchard prevents the radiation 

 of heat from the soil and that a slight economy of 

 heat secured in this way at the proper time will be 

 sufficient to save the trees from damage. This 

 method has probably been used more frequently in the 

 United States for the protection of citrus orchards 

 than in any other connection. It has never proved 

 very successful nor found general favor in actual 

 practice. It is doubtful if any practical peach 

 grower of sound judgment is placing any reliance on 

 this method at the present time. 



It is to be observed in connection with this 

 method, of course, that the purpose is to produce 

 a smudge and not a heat. Material is used, there- 

 fore, which emits a dense smoke rather than that 

 which blazes and burns easily. The old-fashioned 

 method is to start a series of fires along the wind- 

 ward side of the orchard using good strong burning 

 kindling at the outset. As soon as these fires are 

 fairly under way they are blanketed with consider- 

 able quantities of wet brush, wet hay, old, damp 

 straw or any similar material which is conveni- 

 ently at hand. 



ORCHARD HEATING 



In recent years there has come into somewhat 

 extensive use in certain sections, especially in Rocky 



