Physical soil properties created by three mechanical site preparation treatments (ripper ploughing, disc trenching, and blading) were evaluated to determine which was best at creating plantable microsites on wet soil conditions on three mixedwood boreal sites. The objectives of the study were: (1) to look at the success of the different mechanical site preparation treatments in creating plantable microsites in quantity and quality; (2) to analyze selected microsites in terms of water content and bulk density to determine the most favourable treatment; and (3) to estimate potential soil erosion created by each treatment.

Soil analyses revealed ripper ploughing as the best site preparation treatment in this study, using the hinge microsite as the preferred planting spot. All three treatments resulted in an improvement of physical soil conditions compared to the control, although the differences among treatments were not as big as expected. More hinge than berm or trench microsites were created by ripper ploughing and disc trenching. Hinge were superior microsites compared to the others and they were characterized by a thin organic layer with a good mixture with mineral soil. Hinge microsites in ripper ploughing had faster drainage and better bulk density conditions than those in disc trenching. Berm microsites had a poor mixture organic matter and mineral soil, resulting in low bulk density, fast drainage, and low water retention capacity. Trench microsited were located on exposed mineral soil and had slow drainage and sometimes high bulk density values, and were frequently waterlogged after heavy rainfalls, especially those created by ripper ploughing. Blading produced drier microsites than the other treatments and wasted plantable space creating the piles. (Abstract shortened by UMI.)