Soils and Topography
In central Canada, upland stands tend to be of higher quality than the lowland peat stands. Here, podzolic soils of the order Spodosols and gley soils of the order Inceptisols are common on gentle slopes underlain by clay-loam or clays that have been derived from glacial tills. Many of these clay soils are derived from calcareous materials and are neutral to slightly alkaline in the B or C horizons. The most productive black spruce stands are found on the better drained sites such as sandy glacial deposits, river terraces, and outwash plains of the order Entisols, usually in association with hardwood species.
In the north, black spruce sites are commonly underlain by permafrost (perennially frozen soils). Black spruce seems to be the tree species best adapted to growing on permafrost soils because of its shallow rooting habit. Often the annual thaw depth (active zone) may be as little as 40 cm (16 in). In northwestern Canada, black spruce often grows in alternating organic and mineral soil layers, on hummock-like mounds that overlie the permafrost (57). In central Alaska, black spruce is found on permafrost sites of shallow wind-deposited loess and on old river terraces. At tree line, it is often found on shallow, poorly developed mineral soils. On most black spruce sites on permafrost, wildfire results in a temporary increase in the thaw depth.
Black spruce is found from sea level in eastern and northern Canada and western Alaska to 1830 m (6,000 ft) in northern Alberta. It is considered to be a tree of interior lowlands, however, and usually grows at between 150 and 760 m (500 and 2,500 ft). In the mountains of Alaska, Yukon Territory, and Northwest Territories, it is often the tree line species at elevations of 300 to 1220 m (1,000 to 4,000 ft). Local topography and drainage seem to be more important than elevation in determining the range of black spruce.
- Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965). U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp. http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm
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