The Effects of Elevated CO sub(2) and Temperature on the Resistance of Winter-Dormant Birch Seedlings (Betula pendula) to Hares and Voles

• Published in: Global change biology Vol. 10; no. 9; p. 1504
• Main Authors: Kuokkanen, K, Niemela, P, Matala, J, Julkunen-Tiitto, R, Heinonen, J, Rousi, M, Henttonen, H
• Format: Journal Article
• Language: English
• Published: 01.09.2004
• Subjects: Betula pendula
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/j.1365-2486.2004.00820.x

At a site in eastern Finland, closed-top chambers were used to study the effect of elevated atmospheric carbon dioxide and temperature on the biomass and growth of silver birch Betula pendula seedlings, on the secondary chemistry of the top and basal parts of the seedlings, and on the resistance of seedling stems to hares Lepus timidus and voles Migrotus agrestis. The treatments included: ambient CO sub(2) and temperature, elevated CO sub(2) and ambient temperature, ambient CO sub(2) and elevated temperature, and elevated CO sub(2) and temperature. Results showed that both elevated CO sub(2) and temperature significantly increased shoot biomass and height, but only elevated CO sub(2) significantly increased total biomass. Elevated CO sub(2) had no significant effects on stem chemistry, whereas elevated temperature significantly increased the concentration of salidroside in the top part of the stems and decreased the concentration of betuloside in the basal part of the stems. Elevated temperature also significantly decreased the concentration of condensed tannins in the top part of the stem. No effect on the palatability to voles was observed, but elevated temperature significantly decreased the palatability of the top part of stem to hares, and a significant CO sub(2) temperature interaction was observed.