PINUS PONDEROSA, Lawson. 

 Western Yellow Pine. Bull Pine. 



Size. Of western pines next to sugar pine in size. Average 125 to 

 140 ft. by 3 to 4 ft. Maximum 200 by 8 ft. 



Growth. Rate of growth is rapid and well sustained. A study 

 of 45 trees in Arizona gave 10 inches for 66 years, 15 inches for 110 years 

 and 20 inches for 173 years. Life is from 350 to 500 years. 



Root System. Tap. 



Bole. Massive, straight trunked, cylindrical. 



Crown. Long, narrow, open; branches huge and bent. 



Tolerance. Intolerant. Demands much light, especially in older 

 age. Stands thin out rapidly after 10 to 15 years of age. Mature trees 

 rarely closer than 30 feet. Crowns seldom touch. 



Wood. Rather light, fine grained, strong; 29 pounds. 



Reproduction. Seed production prolific; best after 50 years old. 

 Good seed years every 3 to 5 years; some each year. Average 1 to 6 

 pounds of seed per tree. Cones mature early in August of the second 

 summer; seeds shed chiefly in September and finished by early winter. 

 Scattered 500 to 700 feet by the wind. Mature tree can seed J acre in 

 seed year. Seed fairly large; winged. Germination natural sowing 

 50%; artificial planting 60 to 80%. Seedlings in the south require 

 shelter; in the north they grow in the open. 



Range. Northern Mexico and Lower California to southern 

 British Columbia (with var. scopulorum in the Rocky Mountain region). 

 Optimum, Washington, Oregon, Idaho, Montana. Altitude in north, 

 low foot-hills nearly at sea-level to 5000 feet; generally 1000 to 4000 feet; 

 in south, 1000 to 9000 feet; generally 5000 to 8000 feet. 



Climate. Temperature -28 to 110 Fahr.; precipitation 10 to 50 

 inches; humidity, low. 



Soil. Inhabits dry and moist slopes, tops, ridges and canyon 

 bottoms. Grows on all soils from glacial drift to clay; dry or well 

 drained; sandy or gravelly most characteristic. Requires little soil 

 moisture because of its very deep roots. 



Association. Occurs in pure extensive stands and in mixture with 

 conifers and broad leaves. In Washington and Oregon, pure (with 

 western larch and Douglas fir occasionally) . In Sierras pure occasionally, 

 and with sugar pine, incense cedar, Douglas fir, white fir, red fir, Kellog 

 oak, and occasionally the big tree. In British Columbia with Douglas 

 fir and western larch. 



General. Commercial importance is very great. In Canada in 

 1912 it was eleventh in rank, with a cut of 54 million feet board measure, 

 or 1.2% of the total lumber cut. Average mill price $16.30. 



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