Short-term effects of organic matter scalping on the growth and nutrition of black spruce and jack pine seedlings planted in the boreal forest

Scarification contributes to creating planting microsites for reforestation by mixing organic matter (OM) with the upper layers of mineral soil. However, on some boreal sites characterized by a thick humus layer and dominated by ericaceous shrubs, competition seems to limit the benefits of scarification. A potential solution would be to remove OM completely through scalping. The objective of our study was to compare the short-term effects of scarification and scalping on the growth of Picea mariana and Pinus banksiana on such sites. After three growing seasons, we explored the relationships between seedling growth, groups of competing vegetation species, planting depth and distance to the nearest OM accumulation. The two treatments had similar effects on these variables. Growth on plots subjected to scalping was independent from the distance to OM. Planting depth had a nil or positive effect on seedling growth. Pinus seedlings largely outgrew Picea seedlings. However, the lack of short-term difference bet...