,- Lund University, Department of Earth and Environmental Sciences, Lund, Sweden (anders.lindroth@nateko.lu.se)
In ICOS site Norunda, Sweden, CO2 fluxes and meteorology have been measured since 1994 in a mixed pine/spruce forest. Tree cores were collected in 2020 and ring widths were used to estimate annual above and below ground increment using allometric functions. Weather data during 1995 to 2022 showed increases in air temperature (0.044 K/yr), short-wave radiation (0.44 W/m2/yr) and vapour pressure deficit (0.092 kPa/yr) while precipitation did not show any trend. The earlier start of the growing season caused the season length to increase with 0.86 days/yr. Net ecosystem exchange showed a weakening (more positive) trend while no trends were detected in GPP and RECO. Tree growth showed a decreasing trend with time but no correlation with GPP and RECO. Carbon use efficiency defined as tree growth divided by GPP showed a decreasing trend with time.
How to cite: Lindroth, A., Edvardsson, J., Holst, J., Linderson, M.-L., and Mölder, M.: Trends in Long-Term CO₂ Fluxes in Relation to Weather and Tree Growth in a Mixed Hemiboreal Forest, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6292, https://doi.org/10.5194/egusphere-egu26-6292, 2026.
