PROPERTIES AND THEIR RELATION TO USES OF WOOD 161 



and yew. Young trees have a much higher percentage of sapwood 

 than old, mature veterans. Hickory, maple, ash, beech, and some of 

 the pines generally have large portions of their trunk in sapwood. In 

 some species, like cottonwood, willow, spruce, the true firs, and hem- 

 lock, there is comparatively little difference in appearance and value 

 between the heartwood and sapwood. The usual darker color of heart- 

 wood is caused by the deposition of certain tannins, gums, resin, etc. 

 Hence, the heartwood is commonly heavier, harder, and more durable, 

 and it contains much less moisture. Therefore, heartwood is generally 

 much more valuable than sapwood. In some phases of utilization, 

 however, as for spools, spokes, and handles, only sapwood is desired. 

 For example, handles used for axes, hammers, hoes, and shovels, cut 

 from second-growth hickory and ash sapwood, are preferred on our 

 markets. White maple, or the sapwood of the maple tree, is some- 

 times preferred to the heartwood. In many species, sapwood may de- 

 grade lumber sawed from it. For example, two grades may be cut 

 from the same red gum tree. The lumber cut from the heartwood is 

 known as red gum lumber, whereas that cut from the sapwood is gen- 

 erally referred to as sap gum. Sapwood may be treated with pre- 

 servatives more readily than heartwood. This is very important in 

 some species. Most of our railroad cross ties, poles, posts, and fre- 

 quently piling and mine timbers are treated with chemical preserva- 

 tives to prolong their life in service. 



Species with wide wood rays such as oak, beech, and sycamore 

 present a beautiful silver grain when sawed radially or at right angles 

 to the annual rings. Wavy and curly grain are frequent variations 

 in the growth of many species, especially in hard maple and occa- 

 sionally in redwood and yellow birch. 



Custom has been responsible for naming our broadleaved or de- 

 ciduous trees hardwoods, and all our narrow leaved evergreens as 

 conifers or softwoods, but these terms are susceptible of further ex- 

 planation. Both are misnomers when taken literally. Some conifers 

 such as larch and cypress are not evergreen but deciduous, dropping 

 their leaves every autumn. Furthermore, many hardwoods are much 

 softer in their wood structure than some of our softwoods, and some 

 softwoods like larch, longleaf pine, and Douglas fir are much harder 

 and heavier than some of the so-called hardwoods such as basswood, 

 willow, cottonwood, yellow poplar, catalpa, buckeye, and red gum. 



The hardwoods are generally divided into two broad classifica- 

 tions, that is, those which are ring-porous, like oak, ash, hickory, elm, 

 chestnut, and catalpa, and those which are diffuse porous red gum, 

 yellow poplar, willow, birch, maple, basswood, and beech. The former 



