307 



WHITE PINES IN EASTERN NORTH AMERICA 209 



(1959) in New York state showed that there were far fewer weevil ings per 

 tree on P. pence than on P. stvobus. 



Santamour (1965a, b; 1967) studied insect-induced crystallization of 

 white pine resins as a possible criterion for resistance assessment. His 

 results suggested that at least two of the species which should be used 

 in any Pissodes -resistance breeding program, namely P. montioola and P. 

 peuce , may also contribute some degree of resistance to the white pine 

 cone beetle, Conopththoms ooniperda Sz . 



Balkan pine may also be a useful species for planting in regions 

 where air pollution is a problem. Greenhouse studies by gas exchange 

 analysis showed that P. peuce needles had a higher level of SO2 tolerance 

 than did needles of P. sylvestris. This was not the case with P. strobus 

 (Enderlein and Yogi, 1966). 



:-. k?yjd:zu franch. 



Armand pine, P. arrr,andii 3 has not been widely planted in North 

 America, possibly because it is not as winter-hardy as many of the other 

 white pines. Young specimens at the Morris Arboretum near Philadelphia 

 grew rapidly but developed crooks as a result of winter dieback. The 

 species has survived at Rochester, New York, where the trees have poor 

 form and have grown at the rate of about 0.3 m in height per year 

 (Wright and Gabriel, 1959), and at the Morton Arboretum near Chicago, 

 where three specimens were 3.5 to 6.0 m in height at age 25. One had 

 multiple stems (R. M. Nordine, personal communication). Grafts from these 

 trees have not survived in northern Ohio. In a test in Arkansas, only 

 20 percent of a small group of seedlings was alive at age 2 (Schmitt 

 and Namkoong, 1965). Armand pine has survived at Placerville, California 

 (Liddicoet and Righter, 1960) but the trees are in poor condition (R. J. 

 Steinhoff , personal communication) . 



Because of the wide elevational and geographical distribution of the 

 species in Taiwan and southwestern and southcentral China, it is possible 

 that hardier genotypes could be introduced into North America. Armand 

 pine is found at altitudes as high as 3,500 to 4,000 m in the spruce-fir 

 belt of western Szechwan province (Wang, 1961). 



The scanty evidence available indicates that the species is of more 

 interest as an ornamental and a source of blister rust resistance than as 

 a timber tree. It has a rather open crown, with wide-spreading branches 

 (Fig. 6A) . The apparent barrier to crossing with any species but P. 

 larribertiana may preclude the use of its hybrids in regions with a cold 

 winter climate. The species seems, however, to merit further testing 

 if seed collections can be obtained. 



P. CEMBRA L. AND P. SIBIRICA DU TOUR. 



The Swiss and Siberian stone pines have often been considered to be 

 varieties or races of a single species. They are winter-hardy through- 

 out most of the United States and at least as far north as Dropmore, 

 Manitoba, in Canada at latitude 51°N. (Rehder, 1949; Wyman , 1965). Both 

 species are very slow-growing in North America and of little value for 

 timber production. A specimen of P. cembra in New York state was 100 

 years old and 18 m tall in 1957; another was 80 years old and 12 m tall 



