FROST PROTECTION. 



341 



trees are in great danger of severe injury from a second 

 cold wave. The blanket of thick foliage serves as a very 

 material protection 

 to the branches. 



On the Twigs. 

 The young, tender 

 growth of the trees 

 may be injured to 

 some extent by cold 

 sufficiently intense 

 to defoliate the tree 

 without severe in- 

 jury being done to 

 the larger branches. 

 Much depends, of 

 course, upon the de- 

 gree of dormancy. 

 If sufficiently dor- 

 mant, the twigs will 

 resist a considerable 

 degree of cold; but, 

 of course, they are 

 much more susceptible to injury than the branches. It 

 may be stated as a rule that the resistant power of a branch 

 becomes less and less as it decreases in size, or in other 

 words varies directly with the diameter. Large branches 

 are injured only by intense cold, and the top of a tree may 

 be very decidedly cut back by frost before the large 

 branches are injured. The exact amount of injury to the 

 twigs cannot be determined until sometime after the frost 

 occurred. 



On the Trunk. No portion of the tree can withstand 

 more cold than the trunk. When severely frozen, however. 



Fig 1 . 76. Effects of a slight frost on 

 growing- orange tree. Nearly all the 

 leaves have dropped. 



