THE FOREST TREES. 215 



The Forest Trees. 



Harry Nicliols Whitford. 



(The material contained in this and the other botanical lectures is 

 the outcome of a series of talks given at the biological station of the Uni- 

 versity of Montana at Bigfork, Montana, during the summer of 1902. The 

 description of the conifers is intended to be an aid to the identification 

 of the trees for the use of those not acquainted with botanical terms. In 

 nearly all cases the points of difference between the trees have been 

 tried and found applicable in determining the species. In the prepara- 

 tion of the key and descriptions, the author has made free use of the 

 manuals covering the region and of Sargent's "Sylva of North America.") 



An attempt has been made to show why there are prairie and forest 

 formations. In the forest formation itself there are places where there 

 are no trees, and in certain situations some trees will grow where others 

 will not. It will not be out of place to ask why these things are so. But 

 before proceeding, it is desirable to become acquainted with the kinds 

 of trees that are found in the state. This enquiry will be confined to 

 that group of trees called conifers, for the others form an inconspicuous 

 part of the forest. Not only must the trees be known, but also their 

 habits, so that what they will do in certain situations can be predicted. 



It is not always an easy thing to distinguish the different species of 

 trees. The difficulty of recognizing young trees from one another is even 

 greater than with older trees; for the older trees may have cones, and 

 these are, of course, more apt to give a clue to the identification. How- 

 ever, even from older trees cones are often absent. The bark of trees is 

 very characteristic, and lumbermen use this mark to distinguish trees. But 

 hereby mistakes are often made, for the bark is different at various ages; 

 and a tree growing in one situation is likely to have different bark from 

 the same species growing in another situation. 



The leaves perhaps are less variable in their form than the bark, and 

 as they are more often present than the cones, they will serve as a criter- 

 ion in discriminating" the species. With the exception of the western 

 larch, the leaves of the conifers to be described are on the trees the year 

 around, so the character drawn from them can be used in the winter as 

 well as the summer. Since the leaves even on the same tree vary in 

 shape, often more than one character will have to be used. 

 A Key to the Conifers of Montana. 



A. Trees with leaves in clusters, excepting those first appearing on 

 young shoots. 



I. Leaves in clusters of more than five 1. Larix (larch). 



II. Leaves in clusters of two to five 2. Pinus (pines). 



B. Trees with leaves not in clusters. 



