WHITE PINES OF WESTERN NORTH AMERICA 229 



There are six species of white pines native to western North 

 America and Central America. All of them have wide geographic distribu- 

 tions. Three of the species, P. ayacdhuite, P. lambertiana, and P. 

 montiaola, are commercially important; and a fourth, P. strobiformis , 

 occurs mostly as scattered individuals and is harvested only on a small 

 scale. The other two species, P. albiaaulis and P. flexilis , are not 

 often cut for timber but individual trees indicate that selection efforts 

 could produce a more desirable tree if there were a demand for it. 



There have been numerous efforts throughout the world to cross these 

 six species with other white pines and many of the possible combinations 

 have been completed. Several of the hybrid combinations show promise for 

 a variety of uses and for planting areas not having native white pines. 

 Further work using carefully selected parent trees should result in even 

 more desirable hybrids intended for a specific use. 



Planting programs for most of these species are now stopped in most 

 areas awaiting the development of rust-resistant stock. 



LITERATURE CITED 



Bingham, R. T., R. J. Hoff, and R. J. Steinhoff. In press. Genetics 



of western white pine. 

 Critchfield, W. B., and E. L. Little, Jr. 1966. Geographic distribution 



of the pines of the world. U.S. Dep. Agr., Forest Service Misc. Publ. 



991. 97 p. 

 Currey, D. R. 1965. An ancient bristlecone pine stand in western Nevada. 



Ecology 46: 564-566. 

 Dallimore, W. , and A. B. Jackson. 1967. A handbook of Conifevae and 



Ginkgo aaeae. 4th ed. Rev. by S. G. Harrison. St. Martin's Press, 



New York. 729 p. 

 Day, R. J. 1967. Whitebark pine in the mountains of Alberta. Forest. 



Chron. 43: 278-282. 

 Fowells, H. A. 1965. Sugar pine, p. 464-470. In Silvics of forest 



trees of the United States. U.S. Dep. Agr.. Forest Service Agr. 



Handbook 271. 762 p. 

 Haig, I. T. 1932. Second-growth yield, stand, and volume tables for the 



western white pine type. U.S. Dep. Agr. Tech. Bull. 323. 67 p. 

 Harlow, W. M. , and E. S. Harrar. 1950. Textbook of dendrology. 3rd ed. 



McGraw-Hill, New York, Toronto, London. 555 p. 

 Jackson, A. B. 1933. A new hybrid pine. Gard. Chron. Ser. 3, 93: 



152-153; Figs. 68-71. 

 Little, E. L., Jr., and F. I. Righter. 1965. Botanical descriptions of 



forty artificial pine hybrids. U.S. Dep. Agr., Forest Service Tech. 



Bull. 1345. 47 p. 

 Littlecott, L. C. 1969. The social register of big trees. Amer. Forests 



75(2) : 18-25. 

 Loock, E. E. M. 1950. Pines of Mexico and British Honduras. Union 



South Africa Dep. Forest. Bull. 35. 244 p. 

 Martinez, M. 1948. Los pinos Mexicanos. Ed. 2. Ediciones Botas, 



Mexico City. 361 p. 

 Pomeroy, K. B. , and D. Dixon. 1966. These are the champs. Amer. 



Forests 72(5) : 14-35. 

 Righter, F. I., and J. W. Duffield. 1951. Interspecies hybrids in pines. 



A summary of interspecific crossing in the genus Pinus made at the 



Institute of Forest Genetics. J. Hered. 42: 75-80. 



