WHITE PINES IN EASTERN NORTH .AMERICA 



203 



Figure 2. Young Pinus strobus stand in northern Wisconsin 

 (photo courtesy of Wisconsin State Department of Agriculture) . 



poorer was the response of trees of that seed source in the test area 

 (Pauley, Spurr, and Whitmore, 1955). 



In other seed source tests in Wisconsin, Minnesota, Upper Michigan, 

 and Ontario, the northern winter climate appeared to have adverse effects 

 on trees of southern origins (King and Nienstaedt, 1968; Fowler and 

 Heimburger, unpublished data). 



Volume yields have been estimated in older plantations, but informa- 

 tion on seed origin is usually not available. Yield per acre varies 

 widely, increasing with age, site quality and spacing to at least 3 x 3 m 

 (Vimmerstedt , 1962; Gilmore, 1968). In the southern Appalachians, yield 

 is as high as 55,000 board feet per acre (770 m 3 /ha) at 35 years under 

 the most favorable conditions (Vimmerstedt, 1962). 



P. strobus grows well in plantations in the midwestern United States*, 

 where natural disjunct stands are restricted to cool microclimates. In 

 this region, it seems to be adapted to a variety of sites, except heavy, 

 poorly drained soils and strip mine spoil banks. 



P. strobus does not seem to be well adapted in places where it has 

 been planted in western North America. Growth has been poor at Placervilli 

 California, in the Sierra Nevada mountains. Form in Montana plantations 

 is poor (Barnes and Bingham, 1962). Average diameter of 50-year-old 

 plots in one Montana plantation was 24 to 30 cm (Barnes, unpublished 

 data) . 



