Silvicultural options to promote seedling establishment on Kalmia–Vaccinium-dominated sites

Abstract

Seedling growth is often hampered on sites dominated by Kalmia angustifolia. In June 2000, a trial was established on a clear-cut site in Quebec, Canada, with a high cover of Kalmia and Vaccinium species. The objectives were to evaluate how soil scarification and fertilization at the time of planting influence early growth and establishment of black spruce [Picea mariana (Mill.) BSP] and jack pine (Pinus banksiana Lamb.) seedlings. During the first 2 years, scarification reduced Kalmia cover three-fold and doubled the distance from seedlings to the nearest Kalmia stem. Scarification did not increase soil-extractable NH₄-N concentration, and reduced soil potassium, calcium and magnesium. Scarification had no effect on seedling water stress. Seedling growth improved and foliar nutrient concentrations were generally higher in scarified plots than in unscarified control plots. No differences were observed between single- and double-pass scarification for any variables except for ground-level stem diameter of seedlings, which was greater with double-pass scarification (12.1 vs 13.1 mm). Spot fertilization increased seedling growth and foliar nitrogen concentrations. Jack pine growth was greater than black spruce growth, an effect enhanced when seedlings were fertilized.

Keywords:

• Fertilization
• growth
• Kalmia angustifolia
• nutrition
• Picea mariana
• Pinus banksiana
• Quebec
• scarification
• water stress

Acknowledgments

We sincerely thank Francis Cadoret, Jacques Carignan, Daniel Boudreault and Réjean Poliquin for their skilful technical assistance. We are grateful to Dr Robert Jobidon of the Ministère des Ressources naturelles et de la Faune (MRNF) for insightful discussions, Lise Charette (MRNF) for statistical advice, and to staff members of MRNF who performed chemical analyses. We thank Dr Mats Hannerz and one anonymous reviewer for their helpful criticism of our manuscript. We acknowledge the contribution of Neil Anderson (Reforestation Technologies International, Salinas, CA, USA), who supplied slow-release fertilizer. We are also indebted to staff of Abitibi Consolidated Inc. and MRNFP for their help at different stages of this project. Forêt Québec (MRNF) funded this research in consultation with the Fonds québécois de la recherche sur la nature et les technologies through a research grant to Dr A. D. Munson. We also acknowledge a grant from the Programme de mise en valeur des ressources du milieu forestier–Volet I. Use of trade, firm or corporation names is for information only, and does not constitute endorsement by MRNF or the Canadian Forest Service.