THE FOREST TREES. 



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Fig. 8. Cone of Silver or White pine. 



Silver pine (Pinus monticola, Dougl.) : This pine is more frequently 

 known as the white pine, or western white pine. It resembles very much 

 the white pine of the eastern part of the United States. The cones of 

 the former are much longer than those of the latter, and the leaves are 

 more thick and rigid, and usually not so long. No tree in Montana ha& 

 longer cones (Fig. 8) than the silver pine. The leaves of the silver pine 

 are said to remain on the tree from three to four years. The trunk of 

 the young trees has a smooth, thin, light gray bark. In the older trunks 

 it becomes as much as an inch to an inch and a half thick, and is divided 

 into nearly square plates which are very characteristic. When fired, 

 the bark, is easily heated through, the cambium zone (3) is killed, and the 

 tree thus destroyed. In contrast with the western larch the tree is 

 slightly tolerant of shade, that is, it can exist as a seedling in the shade 

 of other trees. In the Flathead valley it is confined to soils that are 

 quite moist. It cannot be said to be a very successful tree here, although 

 in favorable situations it reaches good size. Isolated trees may be 



(3) The cambium zone is the active growing region between wood 

 and iDark that enables the tree to increase in diameter; in the bark and 

 therefore outside the cambium zone is the region that conducts certain 

 food materials from the leaves to the roots. If these regions be killed^ 

 the tree will shortly perish. 



