AgreenSkills session, year: 2nd session, 2012
Receiving laboratory: PIAF Integrative Physics and Physiology of Fruit and Forest Trees Clermont-Ferrand Theix, France
Country of origin : Austria
Monitoring of cold stress in trees by Acoustic Emission Technique, thanks to waveform feature analysis
Winter freezing tolerance is one of the key factors limiting distribution of plants in many ecosystems. Freeze-thaw cycles are inducing embolism in wood vessels, which could lead to death of the tree. Based on the new Acoustic Emissions analysis (AE) method, (i) characterisation of AE signals related to species’ anatomy, (ii) visualisation of ice formation and water flow in freezing stems, and (iii) frost damage in living cells and the xylem of trees growing at the alpine timberline will be analysed. The new method will help to improve future forest management and will enable new insights into mechanisms of frost resistance.
My primary research interest is the understanding of plant ecophysiological responses to environmental changes. I am measuring physiological parameters (hydraulic safety, hydraulic efficiency, freezing tolerance) of trees under drought and frost stress, particularly at the timberline.
During my first training experience (first year of my master’s degree), I learned ecological concepts as I worked with growth dynamics and nitrogen economy in thermic and snowy situations of alpine Cariceae (Laboratory of Alpine Ecology, Grenoble, France). I started ecophysiological research during my second year master training experience, studying winter drought stress in trees growing at the alpine timberline (Institute of Botany, University of Innsbruck, Austria). My PhD was focused on hydraulic efficiency and safety of conifer needles in the context of tree hydraulic architecture (Institute of Botany, University of Innsbruck, Austria). Presently working as an AgreenSkills postdoctoral fellow at INRA, UMR PIAF, Clermont-Ferrand in collaboration with the Institute of Botany of Innsbruck (Tyrol, Austria), I am now extending my ecophysiological knowledge on freezing resistance of trees, using ultrasonic acoustic emissions analysis emitted by branches submitted to freeze-thaw cycles.
Charrier G., Charra-Vaskou K., Kasuga J., Cochard H., Mayr S., Ameglio T. (Submitted to Plant Physiology) Freeze-thaw stress: detection of embolism sensitivity by ultrasonic emissions in the wood of angiosperms.
Charrier G., Charra-Vaskou K., Legros B., Ameglio T., Mayr S. (Under revisions in Agricultural and Forest Meteorology) Changes in ultrasound velocity and attenuation indicate freezing of xylem sap.
Charra-Vaskou K., Charrier G., Wortemann R., Beikircher B., Cochard H., Améglio T. & Mayr S. (2012) Drought and frost resistance of trees: a comparison of four species at different sites and altitudes. Annals of Forest Sciences 69: 325-333.
Charra-Vaskou K., Badel E., Burlett R., Cochard H., Delzon S. & Mayr S. (2012) The hydraulic efficiency and safety of vascular and non-vascular components in Pinus pinaster leaves. Tree Physiology 32: 1161-1170.
Charra-Vaskou K. & Mayr S. (2011) The hydraulic conductivity of the xylem in conifer needles (Picea abies and Pinus mugo). Journal of Experimental Botany 62: 4383-4390.
Mayr S. & Charra-Vaskou K. (2007) Winter at the alpine timberline causes complex within-tree patterns of water potential and embolism in Picea abies. Physiologia Plantarum 131: 131-139.
2011: France Prize of the Interdisciplinary Pole of French Studies for my PhD “Analysis of important aspects in hydraulic efficicency and safety of conifer needles”
2012 (2nd round): Agreenskills Fellow