Alternate Strip Clearcutting in Upland Black Spruce: V. The Impact of Harvesting on the Quality of Water Flowing from Small Basins in Shallow-soil Boreal Ecosystems

Abstract

Streams flowing from six small basins (100-450 ha), dominated or originally dominated by black spruce stands growing on sites with shallow soil over bedrock, were monitored for seven years (1978-1984) near Lake Nipigon, Ontario. Three basins were left uncut. Three basins were harvested, one by patch-cutting, one by clearcutting, and one by stripcutting (in a three-cut pattern, with cutting in 1977, 1979 and 1981). Comparison of streamwater from harvested and uncut basins indicated a greater water yield from the harvested basins, as well as differences in several chemical parameters. Specific conductance, alkalinity, Ca 2+ , Mg 2+ , K + , Na + , and [Formula: see text] concentration increases were statistically significant. Nitrate-nitrogen and total nitrogen (TN) levels generally decreased, the former significantly; pH, [Formula: see text], Cl − , [Formula: see text], [Formula: see text] and total phosphorus (TP) changes were not signficiant.