392 



GENERAL BOTANY 



include flooring, ceiling, and molding and door lumber. In 

 addition the wood is used for a great variety of purposes, for 

 agricultural implements, musical instruments, tools, and excel- 

 sior. Curly and bird's-eye maple (Fig. 49) are of special value 

 for interior finish and decorative effects. The curly effect is due 



FIG. 244. Habit of the American elm (Ulmus americana) in summer 

 Photograph furnished by the United States Forest Service 



to the fact that the grain is wavy, instead of straight as in most 

 trees. Bird's-eye effects may be due to the distortion of the annual 

 wood rings by latent buds, unsuccessful branches, or injuries pro- 

 duced by wood borers. The maple-sugar industry is also one of 

 considerable importance in the east and in the states of Michigan, 

 Wisconsin, and New York. For this purpose the sap of the black 

 maple and that of the sugar maple are the most valuable. 



