224 



FIRST BOOK OF FORESTRY 



In the oak, part of the pith rays are very large, the 

 rest too small to be seen without a magnifying glass ; in 

 chestnut they are all small ; in beech some are large, some 

 small, as in oak ; in maple and cherry most of them are 

 small, but easily seen ; in birch they are all too small to 

 be seen without a magnifying glass. Thus, the pith rays, 

 like "the pores, are valuable marks by which to distinguish 

 the different woods, and they help to make up the pattern, 

 as is clearly seen on almost every kind of hardwood board. 



The Grain. The 

 wood of our trees is 

 made up of cells, all 

 of which are little 

 tubes, which have 

 walls of definite 

 thickness and ap- 



FIG. 83. A " Bird's-eye " Board 



pearance. Each such cell is the abandoned dwelling of a 

 living being, the cell proper, which fed and digested, 

 secreted and worked, built up the little wooden case which 

 we now call cell or fiber, and then died and disappeared. 

 Most cells die during their first year, so that the wood is 

 nearly all made up of little lifeless cases or tubes. 



Some of these tubes are short, others long, some have 

 thick walls, some thin, and most of them have their walls 

 more or less sculptured. The long tubes, which make 

 the bulk of the wood, we commonly call fibers, though 

 there are several distinct kinds of these. 



