THE SILVA OF COLORADO 



n. The Poplars, Aspens and Cottonwoods 

 By Francis Ramaley 



Occurrence and distribution. — The genus Populus, which includes 

 the poplars, aspens and cottonwoods, is represented in Colorado by 

 six well-known species. As a rule, these trees grow along river bottoms 

 and in moist canyons but the quaking aspen forms groves on hill- and 

 mountain-sides at various altitudes. Even this species is found only in 

 rather damp soil, and it is often remarked that a given hillside must be 

 moist because there are quaking aspens growing on it. In the plains 

 region it is possible to locate the courses of streams for long distances 

 by the "cottonwoods" which grow along the banks. In Colorado, with 

 its thousands of acres of needle forest, there are few places with forest 

 cover of broad-leaf trees. Such forest areas as do exist are generally 

 small. In the mountains the trees are aspens, and in the plains region 

 they are " cottonwoods. " The geographical distribution of the different 

 species of cottonwood is not well known because most, people do not 

 distinguish them easily and there has not been a thorough and system- 

 atic study of these trees by competent botanists except in a few parts 

 of the state. 



Economic value. ^ — In Colorado, up to the present time, the wood of 

 species of Populus has been used for fuel and somewhat in the building 

 of fences and sheds. The trees are not very abundant and the supply 

 of such wood soon becomes exhausted. However, there are tracts of 

 bottom-land in the plains region well adapted to the growth of these 

 trees. It may be expected that in time farmers and ranchmen wiU find 

 that a wood-lot is an important part of a farm and they will grow trees 

 just as now they grow grains and fruit. When more valuable trees 

 such as black locust and hardy catalpa are planted the farmer may well 

 reserve a part of his wood-lot for the rapid-growing native poplars. 



' For remarks on the economic value of forests in general, and particularly for Colorado, see the author's 

 previous paper in this series — University of Colorado Studies, Vol. IV, No. 2, p. 109. 



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