LIST WATER LECTURES on Critical Zone Sciences Seminar Series #7

 

What can the high-resolution stable isotope signals of annual tree rings tell us about plant function in a changing climate?

Temperature, radiation and water interact to impose complex and varying limitations on vegetation activity across the world. The availability of water alone strongly limits plant growth in over 40% of the Earth’s vegetated surface, whilst day length and temperature present absolute limits at high latitude and elevated sites. As trees grow they acquire CO2, nutrients and water from their surroundings and every growing season lay down an annual ring of wood that is clearly visible to the naked eye. As the size of these annual rings vary from year-to-year with climate, and because trees are long-lived, annual tree-ring width variations are often used to reconstruct past air temperature and precipitation patterns. Additional tree-ring signals such as wood density and the carbon and oxygen stable isotope compositions of wood are also often highly correlated with climatic drivers, so much so that when studied at high-resolution their within-ring variability can provide insights on weather events and shifts in precipitation regimes. In this lecture I will present our current mechanistic understanding of these stable isotope signals and how our ability to predict their variability within the annual ring can provide insights on past, present and future changes in plant function across the land surface and in response to changes in climate.

Dr. Lisa WINGATE, French National Institute for Agricultural Research, Bordeaux France