58 USES OF COMMERCIAL WOODS OP THE UNITED STATES. 



is tenacious of life and grows in the face of adverse circumstances. 

 In can maintain itself on sand and send its roots down several feet 

 to moisture, while it thrives on land with the water table very near 

 the surface. It is seldom uprooted even by the most violent winds. 

 In early life its growth is rapid, but it matures early. Its average 

 term of life is probably not more than 60 years. In that time it 

 attains a diameter fitting it for railway ties, and a height of perhaps 

 50 or 60 feet. 



Lumbermen cut the jack pine to a diameter of 4 inches, and saw 

 the logs or poles into bed slats, or staves for nail kegs, or plasterer's 

 lath. Thousands of cords of such logs go to the factories each year 

 and meet a demand which must otherwise be met by wood of higher 

 grade. Barrel and keg headings are made for the slack cooperage 

 industry, and box factories draw supplies in large quantities from 

 this wood. The larger logs make dimension lumber, while in some 

 localities fences, including posts and boards, are made of this wood. 

 It is an important source of fuel in many parts of its range. 



Jack pine contributes to the country's pulp supply for the manu- 

 facture of paper. The pulp mills in the Lake States have made con- 

 siderable use of it for this purpose, for which it appears to have 

 about the same value as the scrub pine of Virginia and Maryland. 

 It is used in both the mechanical and chemical processes of manu- 

 facture. 



WESTERN WHITE PINE (Pinus monticola). 



PHYSICAL PROPERTIES. 



Dry weight of wood. 24.3 pounds per cubic foot (Sargent). 



Specific gravity. 0.39 (Sargent). 



Ash. 0.23 per cent of dry weight of wood (Sargent). 



Fuel value. 52 per cent that of white oak (Sargent). 



Breaking strength (modulus of rupture). 8,700 pounds per square inch, or 

 54 per cent that of longleaf pine (Sargent). 



Factor of stiffness (modulus of elasticity). 1,356,000 pounds per 'square inch, 

 or 64 per cent that of longleaf pine (Sargent). 



Character and qualities. Light, soft, not strong, but flexible, grain fine and 

 straight; annual rings wide, summerwood thin, slightly resinous, not conspicu- 

 ous ; resin passages numerous, not large ; medullary rays numerous, obscure ; 

 color light brown or red, the sapwood nearly white ; as easily worked with tools 

 as white pine ; heartwood fairly durable in contact with the soil. 



Growth. Height, 100 to 175 feet ; diameter, 2^ to 3 feet. 



SUPPLY. 



Among the names by which this tree is known are silver pine, 

 white pine, finger-cone pine, mountain pine, soft pine, little sugar 

 pine, mountain Weymouth pine, and western white pine. The last 

 name is most widely used, and distinguishes it from the white pine 

 of the East. Its commercial range lies in California, Idaho, Mon- 



