Alternative Silvicultural Systems for Harvesting and Regenerating Spruce-Dominated Boreal Mineral Wetlands

Authors
Daniel MacIsaac
Graham Hillman
P.A. Hurdle
Resource Date:
2004
Page Length
60

Since 1995, the Canadian Forest Service, Natural Resources Canada has conducted collaborative research with Tolko Industries Ltd. to study alternative silviculture systems as a means of improving conifer reforestation success on mineral wetland sites. Regeneration on these sites is often poor, due to a rise in water table levels and establishment of heavy grass cover following harvest. Narrow clear-cut alternate strips and a patch clear-cut were tested in a white spruce (Picea glauca (Moench) Voss) – black spruce (Picea mariana (Mill.) B.S.P.) – larch (Larix laricina (Du Roi) K. Koch) stand north of Red Earth, Alberta. Performance of planted white spruce, black spruce, and larch, as well as seeded white spruce was monitored on mounded (scarified) and non-mounded (nonscarified) areas following harvest and site preparation in 1997. In addition, groundwater hydrology, microclimate, wind damage, and ground cover were monitored across the site. Five years after harvest, the best survival and growth has been with white spruce planted on mounded microsites. There has been only a small amount of water at the surface; consequently “watering-up” has not been a problem to date. Postharvest windthrow in the strip harvest system was minimal and occurred right after harvest with little subsequent blowdown. This research demonstrates a successful approach to harvesting and regenerating mineral wetland sites, with the objective of ensuring prompt reforestation. This requires prompt postharvest site preparation and planting with vigorous stock to avoid the problems of vegetation competition and partial retention of the overstory to ameliorate ground-level microclimate conditions following harvest.