Germination and early growth of boreal understory plants on 3 reclamation soil types under simulated drought conditions

Abstract

Forest land reclamation after industrial activity requires the re-establishment of self-sustaining ecosystems consisting of native plant species. This greenhouse study determined the germination and early growth of the understory species Leymus innovatus (Beal) Pilg. (Poaceae; hairy wild rye), Chamerion angustifolium (L.) Holub (Onagraceae; fireweed), and Solidago canadensis L. (Asteraceae; goldenrod) in 3 operational reclamation soil types (forest floor-mineral mix, peat-mineral mix, and clay topsoil) under various water stress conditions. Germination of the 3 species occurred only when a standard, high moisture level was maintained; there was essentially no germination when watering was restricted. Furthermore, C. angustifolium germination was greatest in the forest floor-mineral mix. Seedling biomass production in all species and in all soil types increased with higher watering rates; however, the growth increase with watering was lessened on the peat-mineral mix and clay soils, likely because of limited nutrient supplies. Among the species studied, C. angustifolium had the greatest biomass growth potential in higher watering treatments but it was more sensitive to drought with higher mortality in the lower watering treatments. By contrast, L. innovatus and S. canadensis had greater relative biomass production in drier conditions and had greater root:shoot ratios than did C. angustifolium. These results can be used operationally by reclamation practitioners to aid in the development and deployment of appropriate native plant seed mixes to the correct reclamation site and soil types.