280 



THE BOOK OF FORESTRY 



On cutting across a log in addition to the annual 

 growth rings laid on each year by the cambium layer, 

 grayish lines may be seen extending from the heart to 

 bark. These lines, called * ' medullary rays, ' ' are made up 



Courtesy H. P. Brown 



Fig. 64. Section of a non-porous coniferous wood (sequoia), seen 

 through a microscope. The dark band marks the late summer growth. 



of thin-walled cells like the pith in the center. In some 

 hardwoods, like oak, sycamore and maple, these medul- 

 lary rays are very broad and conspicuous, especially 

 when cut along the radius "quarter-sawed" which 

 shows them off to best advantage. In the softwoods 



