Oaks in a high-CO<sub>2</sub> world

Norby, Richard J.

doi:10.1051/forest:19960224

Cited by 18 publications

(16 citation statements)

References 17 publications

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“…For instance, Quercus rubra (oak) had twice the rate of isoprene emission when grown in twice current CO 2 concentration, wheras in Populus tremuloides (aspen) the release was reduced by 30–40% (). Similar responses for oak are reported by Norby (1996) and Tognetti et al (1998). VOC emissions play an important role as tropospheric‐ozone precursors.…”

Section: Co2 and Trace Gas Emmissionsupporting

confidence: 89%

“…The N response disappeared when TNC was subtracted from dry mass. However, in a number of other studies N reduction goes beyond a dilution signal, suggesting some reduction of leaf protein, most likely associated with photosynthetic downward adjustment (e.g., Gifford et al 1996, Norby 1996, Poorter et al 1997, Penuelas and Estiarte 1998). The response can be induced very rapidly as was shown in short‐term CO 2 ‐enrichment in tropical‐forest tree canopies (Würth et al 1998) suggesting, once more, a leaf‐tissue‐specific answer to CO 2 enrichment rather than an overall system response as explanation (Körner and Arnone 1992, Körner et al 1995).…”

Section: Tissue Quality Consumers and Recyclingmentioning

confidence: 96%

“…Since the mycorrhiza‐forming fungus immediately depends on photo‐assimilates, it is obvious that increasing their abundance will have an effect. A fair number of studies have demonstrated substantial mycorrhizal stimulation under elevated CO 2 over a wide spectrum of growth conditions and plant partners (e.g., review in O'Neill 1994, Ineichen et al 1995, Tingey et al 1995, Dhillion et al 1996, , Norby 1996, Godbold et al 1997), but in a few cases the effect was small (e.g., ). A most remarkable phenomenon has been described by Sanders (1996), namely, a host specificity of endo‐mycorrhizal responses to CO 2 enrichment.…”

Section: Tissue Quality Consumers and Recyclingmentioning

confidence: 99%

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BIOSPHERE RESPONSES TO CO₂ENRICHMENT

Körner

2000

Ecological Applications

181

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Atmospheric changes such as elevated CO2 are of global extent, exert prime influences in the remaining wilderness areas, and are second in importance only to effects of land use on ecosystems in most parts of the world. This study is an attempt to summarize, from a biological viewpoint, knowledge of the influences of atmospheric CO2 enrichment on terrestrial ecosystems, as derived from empirical data. I first briefly recall key aspects of the global carbon cycle, mention important conceptual aspects and research tools, and then discuss in greater depth how elevated CO2 is likely to affect vegetation processes. Besides a stimulation of photosynthesis, the most robust findings on plant responses to elevated CO2 are changes in active tissue quality (wider C/N ratio) and effects on community dynamics. Results of experimental work offer a number of plausible projections with respect to future ecosystem processes and organismic interactions, but manipulative experiments appear unsuitable to prove or disprove C sequestration by terrestrial ecosystems. In certain regions, consequences of climatic changes and soluble‐nitrogen deposition are likely to be greater than direct CO2 effects on the carbon balance of vegetation. The significance of the ecosystem approach, the use of fully coupled plant–soil systems, and the consideration of nonlinear responses are highlighted. The current understanding of the CO2 problem offers sufficient justification to urge measures for moderating human forcing of atmospheric change.

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Section: Co2 and Trace Gas Emmissionsupporting

confidence: 89%

Section: Tissue Quality Consumers and Recyclingmentioning

confidence: 96%

Section: Tissue Quality Consumers and Recyclingmentioning

confidence: 99%

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BIOSPHERE RESPONSES TO CO₂ENRICHMENT

Körner

2000

Ecological Applications

181

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“…An acceleration of this tendency since 1940 was also observed by Becker et al (1994) and Badeau et al (1995) on Fagus sylvatica in northeastern France. This radial growth improvement has often been related to changes in environmental factors, such as average temperature in some cases, or more often atmospheric CO 2 and N deposition (Kenk and Fischer 1988;Graumlich 1991;Norby 1996;Spiecker et al 1996;Jacoby and D'Arrigo 1997). Changes in silvicultural practices in managed forests, with stronger and more frequent thinnings in the young forest stands, could also be responsible for a higher radial growth of the dominant trees (Becker 1989;Becker et al 1995;Schneider and Hartmann 1996;Spiecker et al 1996).…”

Section: Discussionmentioning

confidence: 93%

Long-term changes in wood density and radial growth of Quercus petraea Liebl. in northern France since the middle of the nineteenth century

Bergès¹,

Dupouey

Franc

2000

Trees

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Long-term changes in sessile oak (Quercus petraea Liebl.) growth and wood density were studied using cores collected from 99 even-aged high forest stands between 56 and 187 years old, located in northeastern and north-central France. Growth and density trends were tested by analysis of variance and covariance. Two models were applied to two samples, sample A and sample B (sample B being a sub-sample with limited cambial age and calendar date ranges). Model 1 showed a significant increase in radial growth: +35%, +87% and +66% in earlywood width, latewood width and ring width, respectively, from 1811 to 1993 for sample A. Consequently, there was a positive trend in latewood ratio (+14%). A slight decrease in wood density was found: -3.3% and -5.4% for earlywood and latewood density, respectively. Despite an increase in latewood percentage, mean ring density showed a -2.0% decrease. Model 1 applied to a biomass indicator (density×ring width) showed a 62% increase from 10.4 to 16.8 kg m -3 between 1811 and 1993 for sample A. Results for sample B were slightly different: the increase in latewood ratio was not detected. Model 2 showed a change with time in the positive hyperbolic relationship between mean density and ring width. The results are discussed. The decrease in wood density cannot be explained by N atmospheric deposition or by long-term changes in average temperature. Increasing atmospheric CO 2 levels cannot be invoked owing to the present lack of studies. Finally, hypotheses concerning long-term changes in wood anatomical characteristics are proposed.

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“…(Cotrufo et al 1998a;Coûteaux et al 1999;O'Neill and Norby 1996). Although some individual experiments have documented statistically significant declines in [N] in CO 2 -enriched leaf litter (e.g., Cotrufo and Ineson 1996;Cotrufo et al 1994), very few experiments with plants rooted in the ground have done so, and O'Neill and Norby (1996) concluded that the responses of litter chemistry of plants grown in pots or in growth chambers may be artifactual. In fact, because , v v exposed in solardomes.}…”

Section: Litter Decomposition -Co 2 Releasementioning

confidence: 96%

Elevated CO2, litter chemistry, and decomposition: a synthesis

et al. 2001

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The results of published and unpublished experiments investigating the impacts of elevated [CO2] on the chemistry of leaf litter and decomposition of plant tissues are summarized. The data do not support the hypothesis that changes in leaf litter chemistry often associated with growing plants under elevated [CO2] have an impact on decomposition processes. A meta-analysis of data from naturally senesced leaves in field experiments showed that the nitrogen (N) concentration in leaf litter was 7.1% lower in elevated [CO2] compared to that in ambient [CO2]. This statistically significant difference was: (1) usually not significant in individual experiments, (2) much less than that often observed in green leaves, and (3) less in leaves with an N concentration indicative of complete N resorption. Under ideal conditions, the efficiency with which N is resorbed during leaf senescence was found not to be altered by CO2 enrichment, but other environmental influences on resorption inevitably increase the variability in litter N concentration. Nevertheless, the small but consistent decline in leaf litter N concentration in many experiments, coupled with a 6.5% increase in lignin concentration, would be predicted to result in a slower decomposition rate in CO2-enriched litter. However, across the assembled data base, neither mass loss nor respiration rates from litter produced in elevated [CO2] showed any consistent pattern or differences from litter grown in ambient [CO2]. The effects of [CO2] on litter chemistry or decomposition were usually smallest under experimental conditions similar to natural field conditions, including open-field exposure, plants free-rooted in the ground, and complete senescence. It is concluded that any changes in decomposition rates resulting from exposure of plants to elevated [CO2] are small when compared to other potential impacts of elevated [CO2] on carbon and N cycling. Reasons for experimental differences are considered, and recommendations for the design and execution of decomposition experiments using materials from CO2-enrichment experiments are outlined.

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Oaks in a high-CO₂ world

Abstract: Summary — The concentration of carbon dioxide in the atmosphere is one environmental factor that is certain to influence the physiology and productivity of oak trees everywhere.

Cited by 18 publications

References 17 publications

BIOSPHERE RESPONSES TO CO₂ENRICHMENT

BIOSPHERE RESPONSES TO CO₂ENRICHMENT

Long-term changes in wood density and radial growth of Quercus petraea Liebl. in northern France since the middle of the nineteenth century

Elevated CO2, litter chemistry, and decomposition: a synthesis

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Oaks in a high-CO2 world

Abstract: Summary — The concentration of carbon dioxide in the atmosphere is one environmental factor that is certain to influence the physiology and productivity of oak trees everywhere.

Cited by 18 publications

References 17 publications

BIOSPHERE RESPONSES TO CO2ENRICHMENT

BIOSPHERE RESPONSES TO CO2ENRICHMENT

Long-term changes in wood density and radial growth of Quercus petraea Liebl. in northern France since the middle of the nineteenth century

Elevated CO2, litter chemistry, and decomposition: a synthesis

Contact Info

Product

Resources

About

Oaks in a high-CO₂ world

BIOSPHERE RESPONSES TO CO₂ENRICHMENT

BIOSPHERE RESPONSES TO CO₂ENRICHMENT