CO2 enrichment and warming of the atmosphere enhance both productivity and mortality of maple tree fine roots

• Published in: The New phytologist 2004-05, Vol.162 (2), p.437-446
• Main Authors: Wan, Shiqiang, Norby, Richard J., Pregitzer, Kurt S., Ledford, Joanne, O'Neill, Elizabeth G.
• Format: Article
• Language: English
• Subjects: Acer rubrum; Acer saccharum; air temperature; Ambient temperature; Animal, plant and microbial ecology; Applied ecology; atmospheric circulation; Atmospherics; Biological and medical sciences; Carbon dioxide; carbon dioxide enrichment; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; elevated CO2; fine roots; forest ecosystems; Forest soils; forest trees; Fundamental and applied biological sciences. Psychology; global warming; Mortality; plant ecology; plant physiology; Plant roots; Plants; Productivity; red maple (Acer rubrum); Root biomass; root hairs; root mortality; root production; rooting; seasonal variation; Soil temperature regimes; sugar maple (Acer saccharum); temperature
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2004.01034.x

• Fine roots are the key link for plant water and nutrient uptake, soil carbon (C) input and soil microbial activity in forest ecosystems, and play a critical role in regulating ecosystem C balance and its response to global change. • Red maple (Acer rubrum) and sugar maple (Acer saccharum) seedlings were grown for four growing seasons in open-top chambers and exposed to ambient or elevated carbon dioxide concentration [ CO2] in combination with ambient or elevated temperature. Fine-root production and mortality were monitored using minirhizotrons, and root biomass was determined from soil cores. • Both elevated [ CO2] and temperature significantly enhanced production and mortality of fine roots during spring and summer of 1996. At the end of the experiment in September 1997, fine root biomass was significantly lower in elevated temperature chambers, but there were no effects of elevated [ CO2] or the interactions between elevated [ CO2] and temperature. • Deciduous trees have dynamic root systems, and their activity can be enhanced by CO2 enrichment and climatic warming. Static measures of root response, such as soil core data, obscure the dynamic nature, which is critical for understanding the response of forest C cycling to global change.