144 FARM FOEESTRY 



often leaf out in the spring and grow vigorously and there 

 will be no evidence of serious damage having been done. 

 The same trees will die in midsummer. They leaf out in the 

 spring owing to the large amount of food material and moisture 

 stored in the trunks of the trees. As soon as the stored food 

 has been used up and the moisture withdrawn the trees will 

 die. If the bark is peeled away from the lower part of a 

 tree after a fire the damage, if any, can be shown by the 

 scorched color of the cambium layer or inner bark. Trees 

 only partly girdled are badly damaged because of the death 

 of the cambium layer, which subjects the wood to attacks by 

 fungi and insects that may render a large portion of the 

 tree unfit for use. 



