Canadian Forest Service Publications
Growth and survival of seven native willow species on highly disturbed coal mine sites in eastern Canada. 2014. Mosseler, A.; Major, J.E.; Labrecque, M. Canadian Journal of Forest Research 44: 340-349.
Issued by: Atlantic Forestry Centre
Catalog ID: 35400
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Significant differences were apparent in seven native North American willow (Salix) species compared and assessed in common garden field tests for survival, biomass production, and coppice structure on former coal mine sites in New Brunswick, Canada. In most species, percentage survival was relatively constant after the initial establishment phase, allowing good prediction of final survival in the first or second year after establishment. Unrooted dormant stem sections collected from clones of five willow species previously field-tested and selected for survival and growth, survived and grew better on the mine site to be reclaimed than those collected directly from natural populations, demonstrating the ability to rapidly improve survival results based on prior field testing. Survival at ages 5 and 6 improved from an average of 70% to 94% for S. eriocephala Michx. and from 42% to 84% for S. interior Rowlee. The best clones in both species had over 95% survival and had approximately 5–6 t·ha−1 (t = tonne) fresh mass after 2 years of coppice growth. We recommend these two species for use in mine reclamation activities because they grew best overall and had the highest survival rates. Despite poor average rooting ability in S. bebbiana Sarg., S. discolor Muhl., and S. humilis Marshall, some genotypes of these species showed good survival and growth, and further selection for these traits is warranted.
Plain Language Summary
This study used former coal mine sites in New Brunswick to field test large numbers of clones of seven native willow (Salix) species collected from natural populations originating from central and eastern Canada. The aim was to identify a series clones from the most promising native willows for reclamation (rapid re-vegetation) of highly disturbed areas such as mine sites for eventual restoration of high forest cover by using the willows as a nurse crop for natural or artificial succession to higher value conifers. Significant differences were apparent among species in growth performance, survival, and plant growth form. Following establishment of unrooted stem cuttings, the best clones of Salix eriocephala and S. interior had over 95% survival and produced 5-6 Mt ha-1 of fresh biomass after 2 years of coppice growth. We recommend these two species for use in mine reclamation activities because they grew best overall and had the highest survival rates. Despite poor average rooting ability in S. bebbiana, S. discolor, and S. humilis, several clones of these species also showed good survival and growth, and further selection for these traits is warranted. Selected clones of these species are now being used for reclamation activities on base metals mine sites in Ontario, on gold mine sites in Quebec, and could also be used to re-vegetate and restore forest cover on oil sands and oil and gas exploration sites in Alberta.