FROST PEOTECTIOlSr IN LEMOIT ORCHARDS. 
29 
From the data secured in these plats and from observations made 
in other orchards it appears that the Lisbon variety, probably owing 
to its dense foliage and more compact habit of growth, was not quite 
so susceptible to frost injury as the Eureka. These observations 
apply entirely to groves which are not protected by orchard heaters. 
In well-protected orchards there were comparatively small numbers 
of frozen lemons of either the Eureka or Lisbon variety. It therefore 
appears that, although in un- 
protected orchards under similar 
conditions, a greater amount of 
injury is found in Eureka than 
in Lisbon orchards, the differ- 
ence is not sufficiently great to 
warrant any positive statements 
concerning the comparative 
hardiness of the two varieties. 
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SUMMARY. 
Extremely low temperatures 
during December, 1912, and 
January, 1913, caused serious 
damage and loss to unprotected 
lemon orchards in many sections 
of southern California. 
Detailed records of the pro- 
portion of merchantable and 
frozen fruits produced in five 
heated and five nonheated acre 
plats of Eureka and Lisbon lem- 
ons during the calendar year 
1913 and in two comparative 
plats during the calendar year 
1914 in the Corona, Calif., lemon Fig. is— Diagram prepared from the figures presented 
district are presented in this - Table XXII, showing the percentages of mer- 
bulletin. 
These data show that in or- 
chards which were protected 
with an adequate supply of heaters during the cold weather of 1912-13 
a large percentage of merchantable fruit was saved and harvested 
throughout the year. 
In orchards which were not heated a large proportion of the lemons 
picked during the first six months following the freeze were frozen or 
unmerchantable, and the trees did not return to normal production 
until a year had elapsed. 
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chantable and frozen fruits produced on the non- 
heated acre of Lisbon lemon trees, plat 2, as com- 
pared with the nonheated acre of Eureka lemon trees, 
plat 3, during the calendar year 1913. 
