Using Native Willows for Site Reclamation

Canada has 76 native willow species distributed across every region of the country. Willows are usually among the first species to appear following disturbance and can survive on low-fertility sites that often prove difficult for other species. Clones from natural populations of eight native willow species were collected in New Brunswick, Ontario, and Quebec and planted on the shale rock overburden of a former coal mine site in New Brunswick, Canada. Site quality was poor with low organic matter, low nitrogen, and acidity levels ranging from 3.6 to 6.8 pH. The sandbar willow (Salix interior) and heartleaf willow (S. eriocephala) had the best survival and growth. Clones that had been preselected based on prior field testing performed better than clones selected directly from natural populations, indicating that selection based on field testing can rapidly improve performance, even in harsh environments. Sandbar willow may also be a useful species for restoring oil sands sites because it is a natural invader and colonizer of oil sands tailings in Alberta.