12 PRINCIPLES OF AMERICAN FORESTRY. 



little, if any, moisture can be supplied from the roots, 

 which may account for this shrivelled condition. 



Second Growth. Sometimes warm, moist weather in late 

 autumn will cause trees to start a strong second growth in 

 October, which draws on the stored plant-food and perhaps 

 exhausts it, and winter sets in before the tissues have again 

 become hard and stored with food. In such cases trees are 

 liable to injury. No characteristic of hardiness is more 

 important in plants than that of early maturity of wood. 



One part of the tree may start into growth without 

 regard to the conditions of the other parts. For instance, 

 a branch brought into a warm room in winter, without 

 severing it from the tree, will grow for some time. Sun 

 scald is probably due to the bark on the side most exposed 

 to the sun starting into growth very early, after which a 

 sudden freeze destroys the young cellular tissue. 



