256 UNIVERSITY OF COLORADO STUDIES 



Roman days. Short-sighted man, whether barbaric, semi-civilized, or what he may mis- 

 takenly regard as fully civilized, when he has destroyed the forests, has rendered certain the 



ultimate destruction of the land itself This is just one of those matters which it is 



fatal to leave to unsupervised individual control. The forests can only be protected by the 

 state, by the nation, and the liberty of action of individuals must be conditioned upon what 

 the state or nation determines to be necessary for the common safety. 1 



With the continued rise in the price of all kinds of wood the forests 

 of Colorado may be made one of the great economic assets of the state 

 in the future. They will serve for protection to the headwaters of our 

 streams and if rightly managed will furnish a constant supply of timber 

 for industrial and building purposes. 



The cottonwoods of the gulches and river bottoms are, to a con- 

 siderable extent, made use of for fences and for other rough construction 

 work. If farmers and others would take pains to plant these and other 

 more valuable trees they would secure profitable returns. Many of the 

 smaller trees of the state are proving useful as shade trees and still others 

 are being introduced into cultivation for ornamental purposes in parks 

 and private grounds. The thornapples are especially promising as 

 ornamental trees because of both flowers and fruit, while the cotton- 

 woods, hackberries and box-elders are useful for shade. 



Scope of the present study. — The following pages are given up to 

 keys for the determination of the species of trees in the state, together 

 with a somewhat full account of each of the trees of the pine family. 

 It was thought best to describe these trees in some detail on account of 

 their economic value and the general interest which attaches to them. 

 It is impossible at the present time to state fully the distribution of most 

 of the species within the state. Only a small part of the area has been 

 examined by botanists so that the limits of distribution are imperfectly 

 known. 



How to use the keys. — It is necessary to look at Key I for the " ever- 

 greens" (trees of the pine family) and at Key II for any other trees. In 

 each of the keys two choices are open to the student at first, named 

 respectively ia and ib. These two are to be read carefully and which- 

 ever describes the tree under consideration will be used as the beginning 

 of the classification. At the right of line is a figure in parenthesis 



1 Roosevelt, Theodore, "Message to the Congress of the United States," December 8, 1908. 



