LIMBEB PINE. 91 



LIMBER PINE (Pinus flexilis). 

 PHYSICAL PROPERTIES. 



Weight of dry wood. 27.2 pounds per cubic foot (Sargent). 



Specific gravity. 0.44 (Sargent). 



Ash. 0.28 per cent of weight of dry wood (Sargent). 



Fuel value. 60 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). 937,000 pounds per square inch, 

 or 44 per cent that of longleaf pine (Sargent). 



Character and qualities. Wood light, soft, narrow-ringed, compact ; summer- 

 wood narrow, not conspicuous ; resin passages numerous, large ; medullary rays 

 numerous, conspicuous; color light, clear yellow, changing to reddish on expo- 

 sure, the sapwood nearly white. 



Growth. Height, 30 to 50 feet ; diameter, 12 to 36 inches. 



SUPPLY. 



The limber pine is known also as white pine, bull pine, Rocky 

 Mountain white pine, and limber-twig pine. Its drooping limbs are 

 long, slender, and flexible, hence its name. It ranges from Canada 

 southward along the Rocky Mountains to New Mexico and extends 

 westward into Arizona and California. In the Sierra Neva das the 

 upper limit of its range is 12,000 feet. In the Rockies, at the lowest 

 range of this tree's growth and from 4,000 to 6,000 feet elevation, it 

 forms open, scattered stands of round-topped, stunted trees of no com- 

 mercial value, usually in company with Rocky Mountain red cedar or 

 western yellow pine. At timber line from 8,500 to 10,000 feet it 

 assumes a similar or even more stunted form, associating with Lyall 

 larch or other alpine species. At intermediate elevations it occa- 

 sionally produces merchantable timber in company with Douglas fir, 

 and possibly also with white-bark pine, lodgepole pine, Englemann 

 spruce, and alpine fir. 



It is, or was once, the most important timber tree of central Ne- 

 vada, but in many districts it has been cut clean to supply mine 

 timbers, rough lumber, fuel, fencing, and charcoal. It forms a small 

 proportion of the merchantable stand in the Gallatin and the Lewis 

 and Clark National Forests, in company with Douglas fir, lodgepole 

 pine, and white-bark pine. It is a tree of slow growth. Its seeds are 

 practically wingless, and reproduction is restricted to the immediate 

 vicinity of the parent. 



It is commonly a low, thick-trunked, much-branched tree, usually 

 between 25 and 50 feet high, with a trunk anywhere from 5 inches 

 to 3 feet in diameter. In its usual habitat the tree is so stunted and 

 the trunk so short as to yield no merchantable logs. In better loca- 

 tions, however, it is possible to cut 10- foot or even longer logs. When 

 mixed with other species in sheltered canyons it is a tall, straight 

 tree, in shape somewhat similar to lodgepole pine. As compared with 



