The Poplars 163 



the ground cover under which the conifers are able to develop, 

 until they crowd out the quick-growing and short-lived poplars, 

 the conifers themselves to be replaced in tune by the more 

 enduring hardwoods. 



The aspen is the ''white poplar" of the prairie. Its clean 

 slender trunks furnished the pioneer with logs for his building, 

 posts for his barbed wire fences and fuel through the long 

 winter. It is the only tree that seems to have vitality enough 

 to successfully compete with grass for the possession of the soil. 

 An aspen grove will spread outward over the open prairie if 

 protected from fire. In fact, the prairie fire was apparently 

 the only factor which prevented this persevering tree from 

 getting full possession of the prairie, and if man had not ap- 

 peared upon the scene, it might yet have covered these great 

 plains with its graceful silvery stems and tender foliage. 



This tree prefers light dry soil, and will not stand cultivation 

 well. It is very susceptible to fungous diseases and seldom 

 escapes for long, if the grove in which it lives has been cleared 

 out for park or pasture. Unlike the other poplars, it is prop- 

 agated almost entirely by seed. It seldom sends up shoots 

 from the roots, and I have never been able to grow it 

 from cuttings. It grows very readily, however, from seed, 

 and while young grows so rapidly that it can compete success- 

 fully with any other form of vegetation. It does not transplant 

 well, is little used as an ornamental tree and its wood is of purely 

 local value. 



It is distributed all across Canada and northward as far 

 as timber grows. In some places it forms dense forests, in 

 others scattered groves, but more generally is found in mixed 

 forests or in pure stands on lands which have been burned over. 



BALSAM POPLAR. Populus balsamifera. Linnaeus. 



This is the tree called "black poplar" by the pioneer on the 

 prairie. It is also known as Balm of Gilead, although, properly 



