220 



R. J. STEINHOFF 



Figure 5. Mixed stand contain- 

 ing Pinus flexilis (arrow) near 

 Billings, Montana (photo 

 courtesy J. W. Andresen). 



Limber pine has been planted in arboreta and experimental plots but 

 no plantings have been made on a commercial scale. t A group of 4 trees at 

 the Institute of Forest Genetics in Placerville, California, averaged 

 42 feet tall and 11 inches in diameter at 32 years of age (Institute of 

 Forest Genetics, Placerville, Calif., unpublished data) . Wright (1958) 

 reported that some limber pines in Philadelphia were growing faster than 

 eastern white pines {Pinus strobus L.) planted nearby. A 24-year-old tree 

 in Wooster, Ohio, is 37 feet tall and 6 inches in diameter (H. B. Kriebel, 

 personal communication) . Several provenance test plantations recently 

 have been established in the north-central United States from stock grown 

 at Michigan State University. While many of the trees present in arboreta 

 and parks are nultistemmed, others indicate that trees suited to lumber 

 production could be obtained with proper selection. The species appears 

 to be moderately to highly susceptible to the white pine blister rust 

 disease (.Bingham 2 ) . 



Limber pine has been successfully crossed with P. strobiformis and 

 P. monticola (Little and Righter, 1965); and with P. ayacahuite , Pinus 

 qriffithii McClell. (syn. P. wallichiana A.B. Jacks.), and P. strobus 

 (Wright, 1959). A cross with F. albicaulis produced two seedlings which 

 gave indication of being hybrids but they were accidentally destroyed 

 before verification could be completed (W. B. Critchfield, personal 

 communication). The P. flexilis x P. griffithii hybrids at Placerville 

 were 11 feet tall at 10 years (Little and Righter, 1965). 



