Wood properties of trembling aspen and paper birch after 5 years of exposure to elevated concentrations of CO2 and O3

• Published in: Tree physiology Vol. 28; no. 5; pp. 805 - 813
• Main Authors: Kostiainen, Katri, Kaakinen, Seija, Warsta, Elina, Kubiske, Mark E, Nelson, Neil D, Sober, Jaak, Karnosky, David, F, Saranpaa, Pekka, Vapaavuori, Elina
• Format: Journal Article
• Language: English
• Published: 01.05.2008
• Subjects: Betula papyrifera; carbohydrates; carbon dioxide; cell walls; climate change; elevated atmospheric gases; forest trees; greenhouse gases; lignin; ozone; plant extracts; plant response; Populus tremuloides; stemwood; tree growth; uronic acids; vessel lumens; wood anatomy; wood chemistry
• ISSN: 0829-318X; 1758-4469
• DOI: 10.1093/treephys/28.5.805

We investigated the interactive effects of elevated concentrations of carbon dioxide ([CO2]) and ozone ([O3]) on radial growth, wood chemistry and structure of five 5-year-old trembling aspen (Populus tremuloides Michx.) clones and the wood chemistry of paper birch (Betula papyrifera Marsh.). Material for the study was collected from the Aspen FACE (free-air CO2 enrichment) experiment in Rhinelander, WI, where the saplings had been exposed to four treatments: control, elevated [CO2] (560 ppm), elevated [O3] (1.5 x ambient) and their combination for five growing seasons. Wood properties of both species were altered in response to exposure to the treatments. In aspen, elevated [CO2] decreased uronic acids (constituents of, e.g., hemicellulose) and tended to increase stem diameter. In response to elevated [O3] exposure, acid-soluble lignin concentration decreased and vessel lumen diameter tended to decrease. Elevated [O3] increased the concentration of acetone-soluble extractives in paper birch, but tended to decrease the concentration of these compounds in aspen. In paper birch, elevated [CO2] decreased and elevated [O3] increased starch concentration. The responses of wood properties to 5 years of fumigation differed from those previously reported after 3 years of fumigation.