Wood properties and ring width responses to long‐term atmospheric CO₂enrichment in field‐grown loblolly pine (Pinus taedaL.)

Abstract

Loblolly pine (Pinus taeda L.) were grown in the field, under non-limiting nutrient conditions, in open-top chambers for 4 years at ambient CO 2 partial pressures (pCO 2 ) and with a CO 2 -enriched atmosphere (+ 30 Pa pCO 2 compared to ambient concentration). A third replicate of trees were grown without chambers at ambient pCO 2 . Wood anatomy, wood density and tree ring width were analysed using stem wood samples. No significant differences were observed in the cell wall to cell lumen ratio within the latewood of the third growth ring formed in 1994. No significant differences were observed in the density of resin canals or in the ratio of resin canal cross-sectional area to xylem area within the same growth ring. Ring widths were significantly wider in the CO 2 -enrichment treatment for 3 of 4 years compared to the ambient chamber control treatment. Latewood in the 1995 growth ring was significantly wider than that in the ambient control and represented a larger percentage of the total growth-ring width. Carbon dioxide enrichment also significantly increased the total wood specific gravity (determined by displacement). However, when determined as total sample wood density by X-ray densitometry, the density of enriched samples was not significantly higher than that of the ambient chamber controls. Only the 1993 growth ring of enriched trees had a significantly higher maximum latewood density than that of trees grown on non-chambered plots or ambient chambered controls. No significant differences were observed in the minimum earlywood density of individual growth rings between chambered treatments. These results show that the most significant effect of CO 2 enrichment on wood production in loblolly pine is its influence on radial growth, measured as annual tree ring widths. This influence is most pronounced in the first year of growth and decreases with age.

Mechanical properties of spruce and beech wood grown in elevated CO2

“…They found an increase in density in wood grown in elevated CO 2 on a poor Podsol soil and a decrease of density under the influence of enhanced nitrogen deposition. Similar to our findings, Telewski et al (1999) found no wood density differences in young Pinus taeda plants grown in elevated and ambient CO 2 . In a comparable study to the one presented here, Ceulemans et al (2002) reported that wood density of P. sylvestris also remained unchanged in elevated CO 2 .…”

“…They also found that increased N deposition had the opposite effect. In contrast, Rogers et al (1983) and Telewski et al (1999) observed no significant changes in average wood density in Pinus taeda in response to elevated CO 2. To our knowledge, very few studies have compared the mechanical properties directly with morphological and anatomical characteristics.…”

Tree-Ring-Reconstructed Summer Temperatures from Northwestern North America during the Last Nine Centuries*

“…This observation is supported by idealized 2 3 CO 2 growth experiments where the overall effect on MXD is equivocal, detected inconsistently across species, years, and site characteristics (cf. Hä ttenschwiler et al 1996;Telewski et al 1999;Kilpelä inen et al 2003;Kostiainen et al 2004;Yazaki et al 2005). …”

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

“…A few studies have addressed changes in wood structure caused by elevated [CO 2 ] (Telewski et al 1999;Yazaki et al 2005). Atkinson and Taylor (1996) showed that elevated [CO 2 ] increased vessel diameters in the ring-porous wood of Quercus robur seedlings.…”