ANGIOSPERM TREES 



285 



heartwood is a dark reddish-brown and is frequendy finished to 

 imitate mahogany. Oil ol wintergreen may be distilled from the 

 twigs and bark. 



Paper birch is the most widely distributed of the North 

 American birches, ranging widely over the northern half of the 

 continent. Besides being useful for its wood, paper birch is 

 valuable as a pioneer tree species in the reforestation of burned 

 over areas, especially in the far north. It is fast growing, but short 

 lived, and is sometimes grown for ornamental purposes. The 

 white, paper-like bark peels off in thin 

 sheets on the older trees and permits 

 ready identification. 



The Alders 



Alders (Alnus) have alternate 

 egg-shaped or oval, usually irregularly 

 toothed leaves which arise from 

 stalked buds (fig. 202). Male alder 

 flowers are much like those of the 

 birches, but the female flowers are in 

 the form of a short spike which ma- 

 tures into a leathery, cone-like fruit. 

 Of the six tree species, only one is of 

 sufficient size and abundance to be 

 commercially important. This is the 

 red alder, which inhabits the Pacific 

 coast forests from southern Alaska to 

 southern California and is the most 



important hardwood tree in this area. It is ordinarily a medium- 

 sized tree but is sometimes found growing to a height of one 

 hundred thirty feet. It occurs in mixture with the important 

 conifers of this region, and is a very rapidly growing species. The 

 wood is a pale reddish brown, somewhat like cherry in grain. 



The Walnuts 



The w^ALNUTS (Juglans) possess alternate, compound leaves 

 consisting of nine to twenty three lance-shaped, pointed leaflets 

 borne on stout twigs (fig. 203). The terminal buds are covered 



Fig. 202. — Alders have irreg- 

 ularly-toothed, oval leaves. 



