SINGLELEAF PINON. 77 



Mexico to Guatemala. In New Mexico and Arizona the growth is 

 scattering and comparatively scarce; the trees are frequently de- 

 formed through fire injury, and the trunks are inclined to be limby. 

 Lumbermen who cut it at their mills are disposed to place small value 

 upon it, not because the wood is poor, but because the supply is small. 

 In appearance the wood resembles eastern white pine, but there is no 

 evidence that it ever passes for it or is substituted for the eastern 

 species. It is lumbered and marketed with western yellow pine. 

 For that reason it is difficult to list its uses separately. This pine 

 has contributed its share to the region's fuel supply arid ranch tim- 

 bers ; but the demand for these has never been large within the tree's 

 range, because much of the region is mountainous and sparsely set- 

 tled. The tree is sometimes called ayacahuite pine. 



SINGLELEAF PINON (Pinus monophylla). 

 PHYSICAL PROPERTIES. 



Weight of dry wood. 35.25 pounds per cubic foot (Sargent). 



Specific gravity. 0.57 (Sargent). 



Ash. 0.68 per cent of weight of dry wood (Sargent). 



Fuel value. 76 per cent that of white oak (Sargent). 



Breaking strength (modulus of rupture). 4,000 pounds per square inch, or 

 25 per cent that of longleaf pine (Sargent). 



Factor of stiffness (modulus of elasticity). 643,000 pounds per square inch, 

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



Character and qualities. Wood moderately light, soft, very weak, brittle, 

 grain coarse, often twisted; annual rings narrow, summerwood thin, not con- 

 spicuous; resin passages few, not large; medullary rays numerous, obscure; 

 color yellow or light brown, sapwood nearly white; not durable in the soil. 



Growth. Height, 20 to 40 feet ; diameter, 12 to 15 inches. 



SUPPLY. 



The botanical and commercial ranges of this unique tree are co- 

 extensive. Wherever it grows it is put to use. The total quantity, 

 considered as timber, is so small that in comparison with some other 

 species, such as western yellow pine or Douglas fir, it is insignificant. 

 Yet it is of such importance that the existence of the population- 

 more in former times than at present has often depended upon it. 

 It is a product of the desert, of sterile plain, barren ravine, and bleak 

 mountain. It maintains its foothold at an elevation of 9,000 feet, 

 on the eastern slopes of the Sierra Nevada Mountains, and descends 

 to a level of 2,000 feet in the hot Colorado Desert in California. It 

 lives where the mercury falls below zero on wind-swept mountains, 

 and it endures a temperature of 122 in the Mojave Desert. Its 

 range covers portions of Utah, Nevada, California, Arizona, and 

 Lower California, the most sterile and arid regions that can be found 

 in this country. For that reason it has few neighbors of the vegetable 



