WHITE PINE IN MIXTURE 23 



years in the shade under the protection of an 

 upper story of White Pine, and partly by the 

 drying out of the roots. The Hemlock has a 

 shallow root system, and suffers severely when 

 the soil about it is dried by exposure to the 

 sun and wind. The same facts explain part of 

 the injury to Hemlock by strong surface fires, 

 an injury which could be avoided under forest 

 management. 



It is easy to see how the Hemlock, in these 

 old forests, might gradually replace the Pine 

 through the operation of its wonderful capacity 

 to endure shade. There are comparatively few 

 Pine seedlings in such dense groups, whereas 

 young Hemlock occurs in abundance. After 

 the old Pine veterans die off it seems likely that 

 the Hemlock will remain. In all probability 

 the many pure or nearly pure Hemlock groups 

 in these mountains originated through the sur- 

 vival by the Hemlock of one species after an- 

 other, because of its great shade-bearing 

 powers. That bodies of Pine occur on land 

 which the Hemlock would tend to occupy to 

 its exclusion is often to be explained by the 

 fact that, although it may once have been 

 driven out, the Pine has returned in the wind- 

 fall clearing made by a storm. The same result 

 would follow a devastating fire. Such accidents 



