FROST PROTECTION IN LEMON" ORCHARDS. 



altitude of that portion of the mesa where these studies were made is 

 about 1,000 feet. The mesa is protected on the south and east by 

 the Santa Ana Range of mountains, having a general altitude of about 

 4,000 feet. It faces the Santa Ana River valley to the north and 

 west, and has an open and unobstructed exposure in these directions. 



Table I. — Climatological record of a lemon orchard near Corona, Calif., for the months 

 of December, 1912, and January and February, 1913} 





December, 1912. 



January, 1913. 



February, 1913. 



Day of 



the 

 month. 



Temperatures 



"Rainfall 

 (inches). 



Notes. 



Temperatures 

 (° F.). 



Rainfall 

 (inches). 



Notes. 



Temperatures 

 (» !<-.). 



Rainfall 

 (inches). 



Notes. 





Maxi- 

 mum. 



Mini- 

 mum. 



Maxi- 

 mum. 



Mini- 

 mum. 



Maxi- 

 mum. 



Mini- 

 mum. 



1 



65 

 GO 

 70 

 67 

 57 

 57 

 59 

 65 



64 

 66 

 73 

 72 

 70 

 66 

 58 

 75 

 78 

 75 

 68 

 ,59 

 61 

 68 

 66 

 62 

 63 

 69 

 67 

 67 

 66 

 64 



47 

 43 

 34 

 34 

 38 

 38 

 33 

 41 

 36 

 34 

 32 

 41 

 39 

 32 

 38 

 32 

 35 

 48 

 44 

 45 

 30 

 44 

 36 

 33 

 31 

 42 

 41 

 31 

 32 

 33 

 33 







74 

 79 

 83 

 59 

 55 

 42 

 52 

 59 

 48 

 49 

 54 

 59 

 68 

 59 

 58 

 55 

 56 

 51 

 58 



(5) 



64 

 56 

 65 

 71 

 77 

 78 

 76 

 78 

 72 

 73 

 78 



35 

 47 

 53 

 32 

 29 

 19 

 25 

 25 

 32 

 32 

 29 

 29 

 32 

 32 

 31 

 42 

 39 

 34 

 40 



35 

 27 

 30 

 44 

 44 

 39 

 40 

 43 

 40 

 38 

 47 







64 

 66 

 ■ 64 

 64 

 63 

 70 

 60 

 59 

 69 

 69 

 64 

 71 

 78 

 73 

 80 

 76 

 72 

 65 

 57 

 57 

 53 

 55 

 52 

 54 

 54 

 54 

 58 

 63 



39 

 41 

 34 

 34 

 42 

 47 

 50 

 47 

 42 

 40 

 39 

 38 

 36 

 39 

 46 

 41 

 42 

 40 

 36 

 29 

 39 

 38 

 30 

 33 

 45 

 35 

 37 

 32 







2 















3 















4 





0) 

 (3) 



(2) 





(') 







5 .. 







Trace. 



0.38 



.25 



.05 





G 









7 









8 . ... 









9 











10 















11 















12 

















13 















14 















15 



0.05 





0.88 

 .33 



.14 









16 







17 











18 











19 











.28 





20 





(3) 

 (') 

 (5) 



Trace. 





(0) 



21 





.32 

 .50 

 .15 

 1.06 

 .98 

 .04 

 .03 





22 











23 .. . 











24 













25 













26 













27 













28 













29 















30 



















31 





































1 Records secured by Thos. C. Sias, weather ob- 

 server for the Corona district. 



2 White frost. 



3 Violent north wind. 



* Violent north wind; minimum temperature on 

 road alongside orchard at 3 a. m., 17°; temperature 

 did not reach 32° until 11 a. m. 



6 Missing. 



6 No damage, owing to clouds and high humidity. 



METHOD OF ORCHARD HEATING. 



Many of the lemon orchards in the Corona district were provided 

 with orchard heaters for the protection of the trees and fruits during 

 the low temperatures of December, 1912, and January, 1913. These 

 heaters, for the most part, were oil burners of simple construction. 

 The type of heater in most common use is shown in figure 2. The 

 fuel used was a low grade of distillate. The heaters varied greatly 

 in size, the smaller ones holding from 1 to 3 gallons of fuel each, while 

 the larger ones each had a capacity of 7 to 9 gallons of oil. Some 

 experimental heaters, having a much larger capacity and arranged 



