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Harvard Forest Symposium Abstract 2018

  • Title: Tree-ring isotopes reflect satellite-based net primary productivity estimates at the biome scale
  • Primary Author: Mathieu Levesque (ETH Zurich)
  • Additional Authors: Laia Andreu-Hayles (Lamont-Doherty Earth Observatory); Martina Hobi (Swiss Federal Institute for Forest, Snow and Landscape Research); William Kolby Smith (University of Arizona); Neil Pederson (Harvard Forest); A. Park Williams (Lamont-Doherty Earth Observatory)
  • Abstract:

    Historical and future trends in net primary productivity (NPP) and its sensitivity to global change are largely unknown because of the lack of long-term, high-resolution data. We tested whether annually resolved tree-ring carbon and oxygen stable isotopes can be used as proxies for reconstructing past NPP. Stable isotope chronologies from four sites within three distinct hydroclimatic environments in the eastern United States (US) were compared in time and space against satellite-derived NPP products, including the Moderate Resolution Imaging Spectroradiometer (MODIS) NPP product (2000-2015) and the long-term Global Inventory Modeling and Mapping Studies (GIMMS3g) NPP dataset (1982-2011). Tree-ring isotopes, in particular oxygen isotopes (δ18O),, correlated strongly with satellite NPP estimates at both local conditions and across large geographical regions in the eastern US. The results are generally consistent among the studied tree species and under contrasting hydroclimatic conditions. These findings represent an important breakthrough for estimating long-term changes in terrestrial productivity at the biome scale.

  • Research Category: Regional Studies; Physiological Ecology, Population Dynamics, and Species Interactions; Historical and Retrospective Studies; Forest-Atmosphere Exchange