NEEDLELEAF WOODS. 



The trees affording these woods cover large areas in the 

 natural forests of the Northern Hemisphere. They exist, but 

 to an unimportant extent, in the South. Cedar, larch, and 

 cypress figure in ancient history, but woods generally were 

 not employed until recent times.* Pine, spruce, hemlock, 

 and other so-called soft woods are of this group. 



Needle-leaved woods are characterized by uniform fibre- 

 conditions, presence of resins, and lighter weights. The 

 vertical structure consists of simple, similar, elongated tubes 

 or cells, tapering and finally closing at their ends, known as 

 tracheids. These are arranged with more or less regularity, 

 and woods are correspondingly easy to work. Pith-rays are 

 scarcely visible, and sections do not show pores. Cavities 

 known as resin-ducts, and which are not real vessels but rather 

 simple intercellular spaces, secrete resins so important in 

 making these woods durable and elastic. Trees afford large, 

 straight pieces. Woods are used in carpentry and heavy con- 

 structions. The total requirement greatly exceeds that for 

 hard woods. 



The resinous, usually evergreen, leaves and the cones are 

 sufficient to identify these trees. Needleleaf, softwood, conifer, 

 and evergreen trees are the same. 



* See Oak, pages il ^/ seq. The woods have always been important in the 

 United States. 



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