EXOGENOUS SERIES-NEEDLELEAF WOODS. 



139 



Hard pine is practically the strongest building wood com- 

 monly obtainable in large-sized pieces in the United States. 

 Trees are usually cut down after having been tapped for two or 

 three years. The Douglas Spruce or " Oregon Pine " (Pseu- 

 dotsuga taxifolia), supplies much of the "hard pine" used on 

 the Pacific Coast. 



Tar, turpentine, resin and similar products included within the term 

 "naval stores," are derived chiefly from the Longleaf and Cuban pines. 

 This industry is one of the leading ones in the South Atlantic States. It 

 used to be thought that the tapping or "bleeding" to which the trees 

 were subjected, might influence the subsequent strength and durability 

 of their woods, and so firm was this belief, that specfications often ex- 

 cluded " bled" lumber. Since most lumber has been "bled" and since 

 mill men make no attempt to separate the "bled" from the "unbled" 

 woods, some trouble has arisen.* An exhaustive investigation f proved 

 that strength, weight and shrinkage are not influenced by bleeding, and 

 that " bled " is as good as " unbled " lumber. The quantities of resin 

 contained in hard pine vary greatly. Similar trees differ widely in this 

 respect. The resin in heartwood varies between five and twenty per cent, 

 of dry weight. Sapwood is much leaner, and since bleeding principally 

 effects sapwood, durability as well as strength is not influenced to any 

 very great extent. Pine resin is called rosin. The Louisville and Nashville 

 Railroad originally specified "unbled" lumber. Some " bled " lumber 

 was erroneously included and the mill offered to take it back if it could 

 be separated from the rest. As the railway engineers were unable to 

 distinguish it, the matter was dropped. 



A confusion exists in the names of the pines. All South- 

 ern pines are commercially known as yellow pines. American 

 white pine is known in Europe as Yellow Pine, and all hard 

 pines are often there referred to as pitch pines. Spruce Pine, 

 Bull Pine and Bastard Pine are names frequently used to hide 

 ignorance. The species palustris has thirty local names. Bo- 

 tanical names should be used to describe the pines. 



* U. S. Forestry Bulletin No. 8. 



t U. S. Forestry Bulletins Nos. 8 and 10. 



