Wood properties of two silver birch clones exposed to elevated CO₂ and O₃

Abstract

Effects of elevated carbon dioxide (CO 2 ) and ozone (O 3 ) on wood properties of two initially 7-year-old silver birch (Betula pendula Roth) clones were studied after a fumigation during three growing seasons. Forty trees, representing two fast-growing clones (4 and 80), were exposed in open-top chambers to the following treatments: outside control, chamber control, 2 Â ambient [CO 2 ], 2 Â ambient [O 3 ] and 2 Â ambientAfter the 3-year exposure, the trees were felled and wood properties were analyzed. The treatments affected both stem wood structure and chemistry. Elevated [CO 2 ] increased annual ring width, and concentrations of extractives and starch, and decreased concentrations of cellulose and gravimetric lignin. Elevated O 3 decreased vessel percentage and increased cell wall percentage in clone 80. In vessel percentage, elevated CO 2 ameliorated the O 3 -induced decrease. In clone 4, elevated O 3 decreased nitrogen concentration of wood. The two clones had different wood properties. In clone 4, the concentrations of extractives, starch, soluble sugars and nitrogen were greater than in clone 80, while in clone 80 the concentrations of cellulose and acid-soluble lignin were higher. Clone 4 also had slightly longer fibres, greater vessel lumen diameter and vessel percentage than clone 80, while in clone 80 cell wall percentage was greater. Our results show that wood properties of young silver birch trees were altered under elevated CO 2 in both clones, whereas the effects of O 3 depended on clone.

Effects of elevated CO2 and nitrogen on wood structure related to water transport in seedlings of two deciduous broad-leaved tree species

“…Atkinson and Taylor (1996) showed that elevated [CO 2 ] increased vessel diameters in the ring-porous wood of Quercus robur seedlings. On the other hand, no obvious effect was found in diffuse-porous woods including that of Populus tremuloides (Kaakinen et al 2004) and Betula pendula (Kostiainen et al 2006), whereas the vessel lumen area increased significantly in seedlings of Quercus ilex under high [CO 2 ] (Gartner et al 2003).…”

Effects of Elevated Ozone on Photosynthetic CO2 Exchange and Chlorophyll a Fluorescence in Leaves of Quercus mongolica Grown in Urban Area

“…The concentration of O 3 has been increasing rapidly because of the anthropogenic emissions of several O 3 -forming gases (Katri et al 2006). This increase is expected to continue unabated for the foreseeable future (Luis et al 1996).…”

A klímaváltozás emberi jogi aspektusai

“…In the boreal forest, soil CO 2 fluxes to the atmosphere increase with increased temperature and atmospheric CO 2 concentration (Niinisto et al, 2004), although many uncertainties remain (Fang and Moncrieff, 2001;Ågren and Bosatta, 2002;Hyvönen et al, 2005). Climate change may induce a reallocation of carbon to foliage (Magnani et al, 2004;Lapenis et al, 2005) and lead to carbon losses (White et al, 2000;Kostiainen et al, 2006;Schaphoff et al, 2006). Climate change may alter the chemical composition and density of wood while impacts on wood anatomy remain uncertain (Roderick and Berry, 2001;Wilhelmsson et al, 2002;Kostiainen et al, 2006).…”

“…Climate change may induce a reallocation of carbon to foliage (Magnani et al, 2004;Lapenis et al, 2005) and lead to carbon losses (White et al, 2000;Kostiainen et al, 2006;Schaphoff et al, 2006). Climate change may alter the chemical composition and density of wood while impacts on wood anatomy remain uncertain (Roderick and Berry, 2001;Wilhelmsson et al, 2002;Kostiainen et al, 2006).…”