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Moderation of CO2 induced gas exchange and growth responses by elevated tropospheric O3
2002
Karnosky, D. F. (Michigan Technological University, Houghton (USA). School of Forestry and Wood Products) | Sober, A. | Sharma, P. | Kubiske, M. | Isebrands, J.G.
Stimulation of photosynthesis by elevated CO2 has been consistently found for aspen but not for maple. Similar responses have been shown for growth. In contrast, O3 causes decreased levels of photosynthesis and growth in aspen but does not appear to impact sugar maple significantly. When the pollutants co-occur, CO2 induced enhancements in photosynthesis and growth are moderated so that trees in CO2 and O3 treatments respond similarly to those in control rings. In this presentation, we will provide a physiological interpretation of our results in modelling growth response under future atmospheric conditions
Show more [+] Less [-]Consequences of elevated CO2 and O3 on birch canopy structure
2002
Kull, O. (University of Tartu, Tartu (Estonia). Institute of Botany and Ecology) | Tulva, I. | Vapaavuori, E.
We studied elevated CO2 and ozone effects in single and in combination on crown structure of two Betula pendula clones. Shoot ramification, shoot length, number of metamers, leaves and buds were measured at four heights in every tree. Chamber effect was substantial on sylleptic branching and on shoot length and ramification. However these responses differed between the clones. Ozone treatment affected shoot length and caused slight decrease in shoot ramification. Elevated CO2 affected appearance of long shoots in complex manner, but in lower crown positions CO2 caused increased number of long shoots in both clones
Show more [+] Less [-]Effects of elevated CO2 and O3 on silver birch rhizosphere and leaf litter decomposition
2002
Kasurinen, A. (University of Kuopio, Kuopio (Finland). Department of Ecology and Environmental Science) | Vapaavuori, E. | Holopainen, J. K. | Holopainen, T.
There is still limited amount of information about the long-term and interactive effects of increased CO2 and O3 levels on larger forest trees growing under natural or semi-natural conditions. Elevated CO2 and O3 might affect the quality and quantity of leaf litter produced and thus change litter decomposition rates and nutrient cycling in the forest ecosystems severely. In this long-term field experiment we studied the effects of realistically increased CO2 and O3 levels on fine root and mycorrhiza growth in ozone-tolerant and ozone-sensitive silver birch clones by root ingrowth core method. We measured rhizosphere soil CO2 efflux plus assessed the total fungal biomass of fine roots and soil by ergosterol analysis
Show more [+] Less [-]Ponderosa pine response to elevated CO2 and nitrogen
2002
Johnson, D.W. (University of Nevada, Reno (USA). Environmental and Resource Sciences) | Ball, J.T. | Hoylman, A.M. | Walker, R.F.
This paper summarizes the data on growth response and N uptake in open-top chambers planted with ponderosa pine (Pinus ponderosa Laws.) treated with both N (0, 10, and 20 g N msub-2 yrsub-1 as ammonium sulfate ) and CO2. Both N and elevated CO2 caused increased growth. The effects of N on growth response to elevated CO2 were assessed in various ways and various interpretations could be drawn depending on which metric was used, including a negative effect of N on growth response to CO2. These calculations suggest that expressing growth as percentages can be misleading, especially when done on a grams per tree basis
Show more [+] Less [-]Growth responses of two silver birch clones to elevated CO2 and O3 during three years of exposure in OTCs
2002
Riikonen, J. (Finnish Forest Research Institute, Suonenjoki (Finland). Suonenjoki Research Station) | Lindsberg, M. M. | Peltonen, P. | Oksanen, E. | Syrjala, L. | Holopainen, T. | Vapaavuori, E.
Atmospheric carbon dioxide (CO2) and ozone (O3) are increasing by 1-2% per year and are expected to double by the year 2100 compared to the end of the last millennium. Carbon dioxide at twice the current atmospheric concentrations has the potential to increase the productivity of forest trees while increasing ozone is expected to cause significant reductions in growth. The present study was undertaken to investigate the effects of CO2 and O3, singly or in combination, on growth and allocation of two European silver birch (Betula pendula Roth) clones under field conditions to verify the future predicitons in regard to silver birch. Our data show that growth of clone 80 was benefitted by ambient CO2 singly and in combination with ambient O3. Clone 4 was more responsive to ambient O3 than clone 80 which is opposite to results from previous pot experiments with these clones
Show more [+] Less [-][Effects of CO2 on the climate]
1987
Midot, S. (Electricite de France (France). Departement Prospective Environnement Communication, Service des Etudes Economiques Generales)
Nitrous oxide emissions from a wheat field in response to elevated carbon dioxide concentration and open-top chamber enclosure
1998
Pleijel, H. | Sild, J. | Danielsson, H. | Klemedtsson, L. (IVL, P.O. Box 470 86, SE-402 58 Goteborg (Sweden))
Comparison of photosynthetic responses to manganese toxicity of deciduous broad-leaved trees in northern Japan
1997
Kitao, M. | Lei, T.T. | Koike, T. (Forestry and Forest Products Research Institute, Hokkaido Research Center, Sapporo 062 (Japan))
Effects of elevated CO2, nitrogen supply and tropospheric ozone on spring wheat-II. Nutrients (N, P, K, S, Ca, Mg, Fe, Mn, Zn)
1997
Fangmeier, A. | Gruters, U. | Hogy, P. | Vermehren, B. | Jager, H.J. (Institut fur Pflanzenokologie, Heinrich-Buff-Ring 38, D-35392 Giessen (Germany))
Vertical gradients of ozone and carbon dioxide within a deciduous forest in central Pennsylvania
1996
Skelly, J.M. | Fredericksen, T.S. | Savage, J.E. | Snyder, K.R. (Department of Plant Pathology, Pennsylvania State University, 108 Buckhout Laboratory, University Park, PA 16802 (USA))