A whole-tree chamber system for examining tree-level physiological responses of field-grown trees to environmental variation and climate change

• Published in: Plant, Cell and Environment
• Main Authors: Medhurst, J., Parsby, J., Linder, S., Wallin, G., Ceschia, Eric, Slaney, M.
• Other Authors: University of Tasmania Hobart, Australia (UTAS), Swedish University of Agricultural Sciences = Sveriges lantbruksuniversitet (SLU), Southern Swedish Forest Research Centre, Department of Plant and Environmental Sciences, department of Plant, Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: Norway spruce; Picea abies; elevated air temperature; elevated CO2; gas exchange; [SDV.EE.ECO]Life Sciences [q-bio]/Ecology; environment/Ecosystems; Norway; Northern Sweden
• Online Access: https://ird.hal.science/ird-00412498; https://ird.hal.science/ird-00412498/document; https://ird.hal.science/ird-00412498/file/Medhurst_et_al_pce_1553.CeschiaNew.pdf; https://doi.org/10.1111/j.1365-3040.2006.01553.x

A whole-tree chamber (WTC) system was installed at Flakaliden in northern Sweden to examine the long-term physiological responses of field-grown 40-year-old Norway spruce trees [ Picea abies (L.) Karst.] to climate change. The WTCs were designed as large cuvettes to allow the net tree-level CO 2 and water fluxes to be measured on a continuous basis. A total of 12 WTCs were used to impose combinations of atmospheric carbon dioxide concentration, [CO 2 ], and air temperature treatments. The air inside the ambient and elevated [CO 2 ] WTCs was maintained at 365 and 700 m mol mol - 1 , respectively. The air temperature inside the ambient temperature WTCs tracked air temperature outside the WTCs. Elevated temperatures were altered on a monthly time-step and ranged between + 2.8 and + 5.6 ∞ C above ambient temperature. The system allowed continuous, long-term measurement of whole-tree photosynthesis, night-time respiration and transpiration. The performance of the WTCs was assessed using winter and spring data sets. The ability of the WTC system to measure tree-level physiological responses is demonstrated. All WTCs displayed a high level of control over tracking of air temperatures. The set target of 365 m mol mol - 1 in the ambient [CO 2 ] chambers was too low to be maintained during winter because of tree dormancy and the high natural increase in [CO 2 ] over winter at high latitudes such as the Flakaliden site. Accurate control over [CO 2 ] in the ambient [CO 2 ] chambers was restored during the spring and the system maintained the elevated [CO 2 ] target of 700 m mol mol - 1 for both measurement periods. Air water vapour deficit (VPD) was accurately tracked in ambient temperature WTCs. However, as water vapour pressure in all 12 WTCs was maintained at the level of nonchambered (reference) air, VPD of elevated temperature WTCs was increased.