348 CITRUS FRUITS AND THEIR CULTURE. 



In severe freezes, slight differences in resistance to 

 cold disappear entirely, but frequently they are distinctly 

 noticeable. 



PROTECTING WITH EARTH. 



Banking to Save the Trunks. No method of protect- 

 ing the trunks of citrus trees from cold is more efficacious 

 than banking. Never yet has a temperature sufficiently 

 low to injure the trunk of a tree through a mound of earth 

 been reached in any of the citrus districts, and implicit 

 confidence can be placed in this method for protecting 

 the parts covered. 



The banks should be placed about the trees early in 

 November. In Northern Florida, for instance, severe 

 frost is likely to occur as early as the middle of the 

 month. If the tree trunks have been slightly touched by 

 frost before the banks are placed about them, very unsatis- 

 factory results are obtained. The bark rots during the 

 winter if it has been slightly frosted and the trees are 

 frequently killed outright in consequence, when they 

 might otherwise survive, provided, of course, that the 

 winter is mild. The best plan is to place the banks about 

 the trees sometime about the beginning of the second week 

 in November. 



The earth should be heaped well up about the trunk 

 so as to protect as much of it as possible. Young trees 

 should not be totally covered however, but a considerable 

 portion should be left exposed. If they are banked too 

 high, respiration will be prevented and death of the trunk 

 and branches will follow. In budded trees the part most 

 susceptible to the effects of cold is the point of union 

 between stock and cion. This point should be close to the 

 ground and the earth should be well banked about it so as 



