Eastern white pine (Pinusstrobus L.), represented by 117 seed sources from different parts of its range in Canada and the United States, was studied for 2 years in a nursery and 14 years at two plantations in Maryland. In the Piedmont Plateau, these populations ranged in survival from 38 to 100%, in height from 3.0 to 8.2 m, and in diameter from 4.3 to 16.8 cm. In the Coastal Plain, they varied in survival from 25 to 100%, in height from 3.0 to 7.8 m, and in diameter from 3.6 to 15.5 cm. Heights and diameters were strongly correlated; both these characteristics were correlated inversely with the latitude (r ranged from −0.38 to −0.67) and directly with the altitude of the seed source (r = 0.22 to 0.31). The latter correlation, however, included a latitudinal component because most high-elevation trees came from the south. Heights in Maryland at 16 years were significantly correlated with heights of similar populations at younger ages studied in 10 other plantations in the eastern United States (r = 0.32 to 0.73) and to the date of bud set by 1-year-old trees (r = 0.23 to 0.51). The most outstanding in growth rate were some sources from Tennessee, Kentucky, and North Carolina. Also, among the northern sources two populations from Norfolk County, Ontario, were distinctly superior.
Sixteen different types of white pine (Pinusstrobus L.) were exposed for 6 h to 1.5 ppm SO2 in controlled environment chambers in 1979. The specimens, except the controls, were potted grafted seedlings, in active growth when treated. Among nine strains from different geographic regions, the least sensitive were trees from Prince Edward Island, Canada; those from New York, Ontario (No. 75), and Illinois were more sensitive; and the most sensitive were specimens from South Carolina. Among five other types, P. strobus cv. Nana, P. strobus cv. Umbraculifera, Brigham clone, and the control seedlings were moderately sensitive, and cv. Fastigiata was the least sensitive. Two sources treated while dormant were affected less than those in active growth.
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