Site index curves and site factors affecting the growth of white pine in southern Ontario
1990
Williams, P.A. | Gordon, A.M. | Taylor, E.P.
The objectives of this project were to develop site index curves and provide soil-site information for southern Ontario white pine and to compare that information to similar information on white pine from other regions and to information on Norway spruce in the study area. Sampling points were selected in unthinned white pine plantations and classified by soil textural class (course, medium, and fine) and depth to distinct mottling (0-16, 16-40, and 40 + in.). Two sets of anamorphic site index curves were constructed from stem analysis data, using a total age of 30 years (SI30) and a breast height age of 25 years (SIBH25) as base ages. Significant differences due to soil factors were found in the number of years it took seedlings to reach breast height (BH) (mean = 6.5 years; range = 3 to 11 years) but not in SIBH25. Years to BH was significantly greater on clayey sites than those with loamy or sandy textures (6.1 vs. 5.0 and 4.9 years). White pine height growth in the study area compared favorably with white pine height growth in New England, Wisconsin, and Ohio. When white pine height growth was compared to the growth of Norway spruce in the study area, SIBH25 values were significantly higher for Norway spruce but years to BH were significantly lower for white pine. On poorly drained sites, site index values for white pine and Norway spruce were similar, but it took 2.2 years less for white pine to reach breast height (7.2 vs. 5.0 years). On imperfectly and well-drained sites, white pine seedlings took less time than Norway spruce to reach BH, but the site index of Norway spruce was much greater.
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