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. Pine, spruce, hemlock, and 

 other so-called soft woods are of this group, which has always 

 been important in the United States. 



Needleleaved 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. There are exceptions, 

 such as the eucalyptus and tulip trees ; but as a rule the great- 

 est tree forms are in this group, their trunks affording large 

 straight pieces eminently suited for construction. The prop- 

 erties of the woods are such that they are preferred in carpen- 

 try and heavy constructions, the total requirement has greatly 

 exceeded that for hard woods. 



The resinous, usually evergreen, leaves and the cones are 

 sufficient to identify these trees. Needleleaf, softwood, conif- 

 erous, and evergreen trees are the same. The name evergreen 

 is not strictly correct, since some species larch and bald 

 cypress shed their needles every year. 



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