THE ORANGE IN CALIFORNIA FROST PROTECTION. 



155 



the spot. The proposition embraced in the covering is to pre- 

 vent the warm air from leaving the immediate vicinity of the 

 trees at night. During the day the earth and trees become 

 warm, but as the night cools the atmosphere the process of 



Roofing over an orange grove at the Everest Rancho, Arlington Place, Riverside 



County. 



radiation sets in and the heat from the earth and the trees is 

 carried off, the cold frosty atmosphere taking its place. The 

 idea was conceived of covering the orchard with canvas, which 

 could be rolled up in the morning and let out at night. One 



Covering shown from beneath. 



acre was covered in this way, but it was found to be too expen- 

 sive and unstable, as the canvas would get wet and decay. 

 The present method costs about $450 an acre. The fruit borne 

 by the trees under this covering has matured perfectly and the 



