As part of a study to determine the parameters for effective scarification and promotion of black spruce natural regeneration, aninvitroexperiment was conducted to assess growth and rooting ability in sandy soils of four bulk densities (0.85, 1.05, 1.25, and 1.45 g cm−3). The experiment included seeds from two origins, one representative of a well-drained upland site and the other, of a poorly drained lowland site. Results show that black spruce successfully established itself in all bulk densities under study. Shoot growth was best in bulk density 1.25 g cm−3with the seeds of upland origin. It was also good for seeds of both origins in the 0.85 and 1.05 g cm−3soils. However, seedlings established in the soil compacted to 1.45 g cm−3showed reduced growth. Bulk densities of 0.85 and 1.05 g cm−3favored deep root penetration, whereas densities of 1.25 and 1.45 g cm−3restricted rooting. As a whole, upland seedlings developed better rooting than lowland seedlings, indicating that the selected sites of origin could represent two distinct ecotypes. As to allocation between shoots and roots, an interaction was found between bulk density and seed origin.