Abbreviations Definitions units Constant values
aa Fractionation during diffusion through air 4.4
ai Fractionation during diffusion through water 1.8
b Fractionation during carboxylation 29
c1 Coefficient of proportionality m3 mol-1 °C 0.0367
Ca Ambient CO2 concentration ppm
Ci Internal CO2 concentration ppm
Ecd Transpiration rate at stand level mm d-1
Ecdmax Maximal transpiration rate at stand level mm d-1
f Fractionation during photorespiration 16.2
gm Internal conductance mol m-2 s-1
gm∞ Infinite value of gi mol m-2 s-1
gC Stomatal conductance at stand level mol H2O m-2 d-1
\(g_{C\hat{\alpha}\ }\) Stomatal conductance at stand level corrected by \(\hat{\alpha}\) mol H2O m-2 d-1
GPP Gross primary production g C m-2 d-1
GPPEC Gross primary production estimated by eddy-covariance g C m-2 d-1
GPPiso/SF Gross primary production estimated by combined method with isotopic data and sapflow measurements g C m-2 d-1
GPPPRELES Gross primary production estimated by PRELES model g C m-2 d-1
LAI Leaf Area Index m2 m-2
MC Molar mass of carbon g mol-1 12
MH2O Molar mass of water g mol-1 18
nD Number of day light hours NA
P145 Atmospheric pressure at 145m a.s.l kPa 99.6
PPFD Photosynthetic photon flux density mol m-2 d-1
R Universal gas constant J mol-1 K-1 8.314
r Ratio of diffusivities of CO2 and water vapour in the air NA 1.6
REW Relative extractable water NA
RH Relative humidity %
S(t) State of photosynthetic acclimation (°C) at time t (day) °C
S0 Threshold value of the photosynthetic state of acclimation °C -5.33
SWCFC Soil water content at field capacity m3 m-3
\(\text{SWC}_{t}\) Soil water content at sampling time m3 m-3
SWCWP Soil water content at wilting point m3 m-3
Ta Ambient temperature °C
TK Temperature K
VPDD Day light mean VPD kPa
VPDZ Normalised VPD kPa
WUEi Intrinsic water use efficiency ppm
\(\hat{\alpha}\) Photosynthetic capacity °C
\({\hat{\alpha}}_{\max}\) Maximal photosynthetic capacity °C
Δ Observed carbon discrimination during gas-exchange
δ13Ca Ratio of heavy to light 13C isotope in the air
δ13Cp Ratio of heavy to light 13C isotope in phloem content
Γ* CO2 compensation point μmol mol-1