KNOBCONE PINE, 93 



and trails for bridges and corduroy. It makes good charcoal. Lim- 

 ber pine has proven the most resistant of any species to sulphurous 

 fumes from copper smelters on the Deerlodge National Forest. It 

 has continued to make thrifty growth where all other species have 

 died from the fumes. 



CALIFORNIA SWAMP PINE (Pinus nmricata). 

 PHYSICAL PROPERTIES. 



Weight of dry wood. 30.8 pounds per cubic foot (Sargent). 



Specific gravity. 0.49 (Sargent). 



Ash. 0.26 per cent of weight of dry wood (Sargent). 



Fuel value. 66 per cent that of white oak (Sargent). 



Breaking strength (modulus of rupture). 14,000 pounds per square inch, or 

 87 per cent that of longleaf pine (Sargent). 



Factor of stiffness (modulus of elasticity). 1,652,000 pounds per square inch, 

 or 78 per cent that of longleaf pine (Sargent). 



Character and qualities. Wood, very strong and hard, compact; summerwood 

 broad, resinous, resin passages few, not prominent; medullary rays numerous, 

 thin ; color, light-brown, the thick sapwood nearly white. 



Growth. Height, 45 to 90 feet ; diameter, 12 to 24 inches. 



SUPPLY AND USES. 



California swamp pine is not abundant and its uses are few, yet 

 the tree has characteristics which give it local importance. It occurs 

 near the California coast, from 100 miles north of San Francisco to 

 200 miles south. In the southern part of its range it is sometimes cut 

 for fuel and for small farm timbers, and in the north it is occasionally 

 employed for skids, rough bridges, and scaffolds in lumber operations. 

 It grows in the vicinity of redwood forests, and in cutting that timber 

 some of the pine is made use of. The seeds blow into the openings 

 where the redwood is cut, and in some localities it is taking posses- 

 sion of the ground. It occupies such soils as it finds vacant, and will 

 grow in cold clay, in peat bogs, on barren sand or gravel, and on 

 wind-swept ridges exposed to ocean fogs. It thrives in full sunlight, 

 or it will grow in shade. Its ability to grow where few other trees 

 can maintain themselves promises some future usefulness, though it is 

 not probable that it can ever be of much importance. The wood is 

 very strong and hard. The tree is known by several names, among 

 them dwarf pine, pricklecone pine, bishop pine, and obispo pine 

 ("bishop" being the English equivalent of the Spanish word 

 "obispo"). 



KNOBCONE PINE (Pinus attenuata). 



PHYSICAL PROPERTIES. 



Weight of dry wood. 21.8 pounds per cubic foot (Sargent). 

 Specific gravity. 0.35 (Sargent). 

 A S h. 0.33 per cent of weight of dry wood (Sargent). 

 Fuel value. 47 per cent that of white oak (Sargent). 



