CHAPTER I. 

 THE STRUCTURE OF WOOD. 



When it is remembered that the suitability of wood for a par- 

 ticular purpose depends most of all upon its internal structure, it 

 is plain that the woodworker should know the essential characteris- 

 tics of that structure. While his main interest in wood is as lum- 

 ber, dead material to be used in woodworking, he can properly un- 

 derstand its structure only by knowing something of it as a live, 

 growing organism. To facilitate this, a knowledge of its position 

 in the plant world is helpful. 



All the useful woods are to be found in the highest sub-kingdom 

 of the plant world, the flowering plants or Phanerogamia of the 

 botanist. These flowering plants are to be classified as follows: 



r I. Gymnosperms. (Naked seeds.) 



1. Cycadaceae. (Palms, ferns, etc.) 



2. Gnetaceae. (Joint firs.) 



3. Conifers. Pines, firs, etc. 

 Phanerogamia, n Angiosperms . (rruits .) 



(Flowering plants ^ Monocotyledons. (One seed-leaf.) 



Palms, bamboos, grasses, etc.) 

 2. Dicotyledons. (Two seed-leaves.) 



a. Herbs. 



b. Broad-leaved trees. 



Under the division of naked-seeded plants (gymnosperms), prac- 

 tically the only valuable timber-bearing plants are the needle-leaved 

 trees or the conifers, including such trees as the pines, cedars, spruces, 

 firs, etc. Their wood grows rapidly in concentric annual rings, like 

 that of the broad-leaved trees ; is easily worked, and is more widely 

 used than the wood of any other class of trees. 



Of fruit-bearing trees (angiosperms), there are two classes, those 

 that have one seed-leaf as they germinate, and those that have two 

 seed-leaves. 



The one seed-leaf plants (monocotyledons) include the grasses, 

 lilies, bananas, palms, etc. Of these there are only a few that reach 



