Restoration of Native Tree and Shrub Species on Reclaimed Grassy Sites

Past silviculture efforts within some legacy reclaimed oil sands development sites in the northeast boreal forest of Alberta have been overtaken by grasses either naturally or through direct seeding. These grasses are competitive and can prevent tree and shrub establishment and development. This study aimed to evaluate a suite of seedling centred site treatments (mechanical and chemical) for their ability to improve seedling establishment success and early growth (rate and form). Treatments included mounding, rototilling with herbicides, shelter with herbicides, and no treatment (control). 3 species were planted – white spruce, green alder and balsam poplar.

(1) Any site treatment is better than just planting in the grass, especially for deciduous species survival; (2) Pre-emergent weed control is require to deal with the seed bank; (3) Mounding with herbicides reduced competitive cover and increased seedling survival and growth compared to no treatment.