Between 1960 and 1966, 21 planting and 14 seeding trials were established to convert aspen stands to spruce-aspen mixedwoods in three Manitoba Forest Management Sections. Scalped strips, varying in width from 2.0 to 3.7 m, were bulldozed in young to over mature aspen stands for planting and seeding. The undisturbed stands between the strips range from 2.7 to 17.7 m wide. Square 0.081 ha (1/5 acre) plots were bulldozed in one area (la). Mineral soil exposure (B horizon) exceeded 75% on 60% of the plantations. Moisture regimes (MR) vary from dry to very moist (MR 0 - 6) according to Hills (1952) although the fresh to moderately fresh range (MR 3 - 4) occurs most frequently. All areas planted or seeded were established for research purposes except for three planted areas in the Whiteshell (11, 12 and 17) which were operational reforestation projects.
In this study, planting on scarified strips proved successful in introducing white spruce into aspen stands. Overall survival of planted white spruce proved best on scalped strips prepared on upland sites (MR 2-4) where there was no excessive moisture or seasonal flooding; where vegetative and overstory competition was relatively light; and where hare and ungulate browsing damage was minima]. Very moist sites (MR 6) exhibited the lowest survival rate.
On the other hand, seedling growth proved best on the fresh to very moist (MR 3 to 6) sites and poorest on the very dry (MR 0) site.
Similar results were obtained on the seeded strips although seedling mortality has been very high and growth extremely slow relative to the planted stock.