208 HOWARD B. KRIEBEL 



Himalayan white pine survives and grows well in the vicinity of 

 Seattle, Washington (Wyman, 1965). It outgrows P. monticola in the Sierra 

 Nevada mountains of California but is not as drought resistant as the 

 western white pine (Duffield and Righter, 1953) . 



The species is a very attractive ornamental because of its long 

 drooping needles and spreading branches (Fig. 5A and Wright, 1958). 

 Pruning is necessary, however, if timber is the objective. Of greater 

 interest to American tree breeders is its breeding value for the intro- 

 duction of vigor and disease resistance into hybrids with native American 

 white pines. 



P. KORAIENSIS SIEB. § ZUCC. 



P. kovaiensis, Korean white pine, is probably one of the hardiest of 

 the white pines. Growth rate varies widely; some specimens in the north- 

 eastern United States have grown only a few to several centimeters per 

 year (Fig. SC) , whereas other have averaged over 0.5 m in annual height 

 growth. The bole form is usually good. One of the best specimens of 

 Korean white pine in the Northeast is at Williamstown, Massachusetts. At 

 age 35, the tree was 18 m tall, 25 cm in diameter and had a perfectly 

 straight trunk (Wright, 1958; Wright and Gabriel, 1959). 



At Wooster, Ohio, height and diameter growth of P. koraiensis trees 

 planted on a 2 x 2 m spacing has been slightly less than that of P. strobus 

 in similar plots nearby. At age 20, average height was 8 m and average 

 diameter 10.5 cm (Aughanbaugh , Muckley, and Diller, 1958). At age 54, 

 2 of 49 trees remain. One is 21 m high and 30 cm in diameter, while the 

 other is only one third as large. 



Studies in the northeastern United States and Canada indicate that 

 Korean white pine has a high degree of resistance to attack by the white 

 pine weevil (Wright and Gabriel, 1959; Heimburger, unpublished data). 

 This characteristic is in itself sufficient inducement for field testing 

 of growth characteristics and adaptability as related to genotype. 



P. PEUCE GRISEB. 



P. peuoe , the Balkan or Macedonian white pine, is hardy throughout 

 most of the United States and southern Canada. It has a dense, narrow 

 crown, fine branches, and a straight bole with little taper. 



Growth is slow to moderate, usually about 0.3 m per year in the 

 northeastern and midwestern states during the first 2 or 3 decades (Fig. 

 5D and Wright and Gabriel, 1959; Aughanbaugh, Muckley, and Diller, 1958; 

 Heimburger, unpublished notes) . One of the oldest Balkan pines in the 

 United States is growing near Boston. It was 15 m tall at age 80 and had 

 a spread of 4.6 m (Wyman, 1965). 



About 1951, A. G. Johnson showed me one P. peuoe tree in the Arnold 

 Arboretum near Boston that had withstood repeated attacks by the white 

 pine weevil, though surrounding trees of P. peuoe and P. strobus were 

 severely damaged. Resistant trees of Balkan white pine have also been 

 found in Ontario. Resistance is apparently the result of heavy resin flow 

 and subsequent healing of the puncture wounds (Fowler and Heimburger, 

 1958; Heimburger, 1958, 1963). Field observations by Wright and Gabriel 



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