ORCHARD HEATING 31 



fruit, but the greater would be the expense of heating; so that 

 for crops of the value we have assumed and at the expense of 

 heating we have given, heating is of doubtful economic value 

 anywhere in the state. (Higher prices usually exist after a 

 freeze because of scarcity of fruit.) 



In California, where it is reported to be a financial success, 

 the frosts usually occur without heavy winds and the high value 

 of the orange or lemon crop makes the cost of heating small in 

 comparison to it. There they also heat to protect the trees from 

 freezing. 



CONDITIONS UNDER WHICH ORCHARD HEATING PAYS 



The experience of orchard men in California seems to show 

 that if farmers are willing to pay the price, they can ward off 

 the effects of many and severe frosts. If they use intelligence 

 and care, having wind breaks, plenty of oil, labor, and heaters in 

 place, accurate thermometers, and accurate forecasts of the 

 weather together with careful organization and cooperation 

 through many neighboring farmers heating simultaneously, 

 there is little doubt that the fruit can successfully be protected 

 from severe frosts. It is doubtful whether fruit can be pro- 

 tected against freezes caused by north winds of 10 miles an hour 

 or more. 



In the following discussion we are goin^g 1 to give the benefit of 

 the doubt in each case to the side of the heating and when we 

 talk of the number of nights of heating we shall assume that the 

 earlier nights when light frosts have simply thinned the buds, 

 are omitted and only on the nights when the frost would actually 

 cut down the final yield in the fall that the heaters would be 

 lighted. 



In calculating the cost of heating an orchard we must not only 

 consider the cost of oil and labor for the night and the cost of 

 placing the pots in the orchard, filling 1 , and gathering them again 

 each year, but we must add to this the interest and depreciation 

 on the orchard heating equipment. We have calculated the inter- 

 est and depreciation per acre per year as follows: 



