PSInet Subdataset: Plant Hydraulics in Two Temperature Central European Forest Ecosystems

This data sets contains plant water potential data from Norway spruce (Picea abies) and European beech (Fagus sylvatica) taking from top-canopy twigs in 2023. The data was primarily taken at 6 p.m. local standard time (CET) to overlap with the Sentinel-1 SAR missing for model validation of forest water status. Twice per site, the diurnal cycles was measured. Temporal resolution: Two different schemes: Seasonal monitoring: April–September, biweekly, evening (6 p.m. local standard time CET) Dirunal samples: 2x per season, peak-of-season, late season (predawn-morning-midday-afternoon-eventing) Sites: Wetzstein: Monospecific managed evergreen needleleaf forest (ENF), Norway spruce (Picea abies) with stand age > 100 years (clear cut in 2024), adjacent to eddy covariance tower (EC) DE-Wet. Leinefelde: Monospecific managed deciduous broadleaf forest (DBF), European beech (Fagus sylvatica) with stand age > 100 years, adjacent to EC tower DE-Lnf. Measurment protocol: Twigs were harvested using a telescope pruner from the eddy covariance tower on the site Specimen: Top canopy (within 3 m of the top crown), sun exposed Transport: Bagged in zip-lock and carried to ground Measured with Scholander pressure chamber model 1505D on the ground (always the same person, project leader) Sample size: 2-3 replica per tree and sampling time 3-4 trees per site Variables (Leinefelde): Manual or automated sampling Unit Sensor location Instrument Plant water potential - pressure chamber Manual MPa chamber unbagged Soil water content - shallow (8 cm) Automated cm3 cm3-1 (volumetric) SWC-DeltaT MLx Soil water content - deep (64 cm) Automated cm3 cm3-1 (volumetric) SWC-DeltaT MLx Precipitation Automated mm Above canopy Thies tipping bucket, Thies Clima, Göttingen, Germany Relative humidity Automated % Above canopy HMP155, Vaisala GmbH, Hamburg, Germany Vapor pressure deficit Automated kPa Above canopy HMP155, Vaisala GmbH, Hamburg, Germany Air temperature Automated C Above canopy HMP155, Vaisala GmbH, Hamburg, Germany Photosynthetically active radiation (PPFD) Automated µmolPhoton m-2 s-1 Above canopy PQS1, Kipp&Zonen, OTT HydroMet B.V., Delft, The Netherlands Incident shortwave radiation Automated W m-2 Above canopy CNR4, Kipp&Zonen, OTT HydroMet B.V., Delft, The Netherlands Net radiation Automated W m-2 Above canopy CNR4, Kipp&Zonen, OTT HydroMet B.V., Delft, The Netherlands Windspeed Automated m s-1 Above canopy 2D sonic anemometer, Thies Clima, Göttingen, Germany Variables (Wetzstein): Manual or automated sampling Unit Sensor location Instrument Plant water potential - pressure chamber Manual MPa chamber unbagged Soil water content - shallow (8 cm) Automated cm3 cm3-1 (volumetric) SWC-DeltaT ML2x Soil water content - deep (64 cm) Automated cm3 cm3-1 (volumetric) SWC-DeltaT ML2x Precipitation Automated mm Above canopy Tipping bucket rain gauge 5.4032.30.008, Thies Clima, Göttingen, Germany Relative humidity Automated % Above canopy CPC1S_5-ME, Mela Sensortechnik GmbH, Mohlsdorf-Teichwolframsdorf, Germany Vapor pressure deficit Automated kPa Above canopy CPC1S_5-ME, Mela Sensortechnik GmbH, Mohlsdorf-Teichwolframsdorf, Germany Air temperature Automated C Above canopy CPC1S_5-ME, Mela Sensortechnik GmbH, Mohlsdorf-Teichwolframsdorf, Germany Photosynthetically active radiation (PPFD) Automated µmolPhoton m-2 s-1 Above canopy SKP 215S, Skye Instruments Ltd, Llandrindod Wells, Great Britain Incident shortwave radiation Automated W m-2 Above canopy CNR1, Kipp&Zonen, Delft, The Netherlands Net radiation Automated W m-2 Above canopy CNR1, Kipp&Zonen, Delft, The Netherlands Windspeed Automated m s-1 Above canopy 2D sonic anemometer 4.3800.00.140, Thies Clima, Göttingen, Germany