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Research article1997Peer reviewed

Site preparation by steam treatment: Effects on forest vegetation control and establishment, nutrition, and growth of seeded Scots pine

Zackrisson, O; Norberg, G; Dolling, A; Nilsson, MC; Jaderlund, A

Abstract

Ericaceous-dominated ground vegetation in boreal forests strongly suppresses tree seedling establishment and growth. Attempts to control this vegetation have led to the large-scale, and often criticized, use of soil scarification and herbicide treatment to control vegetation after cutting. We investigated a new site preparation technique by steam treatment to control ground vegetation dominated by Empetrum hermaphroditum Hagerup in a north Swedish boreal site. Sowing experiments were performed between 1990 and 1993 with Pinus sylvestris L. in four treatments: (1) steamed vegetation, (2) activated carbon added to the soil surface of steamed vegetation, (3) untreated vegetation, and (4) activated carbon added to the soil surface of otherwise intact ground vegetation. Activated carbon was added to adsorb germination inhibitors from E. hermaphroditum leaves and litter. Steam treatment killed field- and bottom-layer species during the first 5 years after treatment. Scots pine seedling establishment was much improved for all seed years by steam treatment when activated carbon was added to the soil. Dry weight of 5-year-old seedlings was 260% higher in steam-treated plots than in untreated plots. Seedlings in untreated vegetation were few and had gained little or even lost important macronutrients when compared with the original seed supply. We interpret the increased growth of seedlings in steamed plots mainly as an effect of reduced interference of forest floor vegetation. We suggest that steam treatment has the potential to be an effective tool to reduce negative influence of competitive ericaceous ground vegetation on tree seedling growth.

Published in

Canadian Journal of Forest Research
1997, Volume: 27, number: 3, pages: 315-322
Publisher: NATL RESEARCH COUNCIL CANADA

      SLU Authors

    • Zackrisson, Olle

      • Department of Forest Vegetation Ecology, Swedish University of Agricultural Sciences

      • Norberg, Gisela

        • Department of Forest Vegetation Ecology, Swedish University of Agricultural Sciences

        • Dolling, Ann

          • Department of Forest Vegetation Ecology, Swedish University of Agricultural Sciences

            • Jäderlund, Anders

              • Department of Forest Vegetation Ecology, Swedish University of Agricultural Sciences

            UKÄ Subject classification

            Forest Science

            Publication identifier

            DOI: https://doi.org/10.1139/x96-172

            Permanent link to this page (URI)

            https://res.slu.se/id/publ/115294