28 USES OF COMMERCIAL WOODS OF THE UNITED STATES. 



Breaking strength (modulus of rupture). 6,900 pounds per square inch, or 

 43 per cent that of longleaf pine (Sargent). 



Factor of stiffness (modulus of elasticity). 637,000 pounds per square inch, 

 or 30 per cent that of longleaf pine (Sargent). 



Character and qualities. Light, soft, weak, brittle; grain coarse; summer- 

 wood narrow, not resinous ; resin passages few, not large ; medullary rays 

 numerous, obscure; color light brown, the thick sapwood nearly white; not 

 durable in contact with the ground. 



Growth. Height, 75 to 100 feet ; diameter, 1$ to 3 feet. 



SUPPLY AND USES. 



Spruce pine is of minor importance, and apparently will remain 

 so. This is due to scarcity and not to lack of value in the wood itself. 

 It is softest of the southern pines and has been compared with white 

 pine, and in some localities is known by that name. It is also known 

 as cedar pine, poor pine, lowland spruce, and Walter's pine. The 

 last name is in honor of its discoverer, who first described the tree 

 in 1788. For seventy-odd years after that it was not recognized by 

 any botanist, though the younger Michaux and others passed through 

 the region where it grows. It is found near the coast of Soutli Caro- 

 lina and in restricted regions of Florida, Mississippi, and Louisiana. 

 It nowhere forms pure forests, except in a few localities where second 

 growth has taken possession of abandoned fields and in openings 

 caused by timber cuttings. It is best developed in northwestern 

 Florida, where trees reach maturity in about 75 years. Soon after 

 that period the timber is apt to deteriorate through decay at the base 

 and red heart at the top. 



Though the wood is soft and has been compared in that respect 

 with w y hite pine, it resembles loblolly in appearance. The sapwood 

 is thick, sometimes constituting three-fourths of the trunk of trees 

 75 years old. The wood shrinks about 10 per cent of its bulk in 

 seasoning. Its fuel value is lower than the other southern pines, on 

 account of its lack of resin. The want of resin excludes this tree 

 from the list of pines valuable for naval stores and confines its value 

 to its use as lumber only. A little of it is cut wherever mill opera- 

 tions are in progress within its range, but the lumber in the market is 

 seldom distinguished from other pines that go with it. 



SAND PINE (Pinus clausa). 

 PHYSICAL PROPERTIES. 



Dry weight of wood. 34.75 pounds per cubic foot (Sargent) 

 Specific gravity. 0.56 (Sargent). 



Ash. 0.31 per cent of dry weight of wood (Sargent). 

 Fuel value. 74 per cent that of white oak (Sargent). 



Breaking strength (modulus of rupture). 7,000 pounds per square inch, or 

 43 per cent that of longleaf pine (Sargent). 



