Abstracts

Forest Ecosystems

A model of the net ecosystem exchange of a scots pine forest is presented. The model has been calibrated with above and below canopy eddy covariance measurements, soil respiration chamber measurements and stem respiration measurements undertaken between 1998 and 2000 near Zotino in central Siberia.

The photosynthetic component of the model consists of a Farquhar-type chloroplast biochemistry linked via analytical solutions to a stomatal model where stomata are considered to optimise the marginal evaporative cost of plant carbon gain (Cowan 1977). Based on long-term calibrations of the model against tree-ring 13C data, as well as responding to light and temperature, stomata and hence photosynthetic rates respond to variations in canopy-to-air vapour pressure difference, changes in soil moisture status and the long-term increase in atmospheric CO2 concentrations this century (Arneth et al., 2001). The canopy respiration module consists of soil, stem and foliar respiration components; each with their own calibrated temperature sensitivity (Shibistova et al., 2002).

In conjunction with long-term climate data, long-term variations in the carbon balance of the stand are examined. Particular attention is paid to the effects of changed precipitation patterns, increasing temperatures and cloudiness variations that have occurred this century.

List of References
Arneth, A., J. Lloyd, H. Šantrková, M. Bird, S. Grigoryev, Y. N. Kalaschnikov, G. Gleixner, E.-D. Schulze (2001) Response of central Siberian Scots pine to soil water deficit and long-term trends in atmospheric CO2 concentration. Global Biogeochemical Cycles (in press)
Cowan, I. R. (1977) Stomatal behaviour and environment. Advances in Botanical Research 4, 117-228.
Shibistova, O., J. Lloyd, O. Kolle, A. Arneth, E.-D. Schulze (2002) Annual ecosystem respiration budget for a Pinus sylvestris stand in central Siberia. Tellus (submitted)

Note. Abstracts are published in author's edition

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