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Harvard Forest Symposium Abstract 2018

  • Title: The International Tree Ring Data Bank (ITRDB) revisited: Data availability and global ecological representativity
  • Primary Author: Shoudong Zhao (Beijing Normal University)
  • Additional Authors: Emery Boose (Harvard Forest); Loic D'Orangeville (University of New Brunswick); Ruben D. Manzanedo (Harvard Forest); Yuan Jiang (Beijing Normal University); Neil Pederson (Harvard Forest)
  • Abstract:

    Aim: The International Tree Ring Data Bank (ITRDB) is the most comprehensive database of tree growth. To evaluate its usefulness and improve its accessibility to the broad scientific community, we aimed to i) quantify its biases, ii) assess the extent to which it represents global forests, iii) develop tools to identify areas that may improve its representativity, and iv) make available a corrected version of the database.

    Location: Worldwide.

    Time period: Contributed datasets between 1974 and 2017.

    Major taxa studied: Trees.

    Methods: We identified and corrected formatting issues in the individual datasets of ITRDB and compiled them into a single dataset. From there we calculated the representativity of the ITRDB with respect to species, spatial coverage, climatic regions, elevations, need for series update, climatic limitations on growth, vascular plant diversity, and associated biodiversity. We combined these metrics into a global Priority Sampling Index (PSI) to highlight ways to improve ITRDB representativity.

    Results: Our refined dataset provides access to a network of >52 million growth data points worldwide. We found, however, that the database is dominated by trees from forests with low diversity, in semi-arid climates, coniferous species, and in western North America. Conifers represent 81% of the ITRDB. Even in well sampled areas, such as North America, broadleaf species are poorly represented. The PSI stressed the need to increase the diversity of the database in terms of broadleaf species and poorly represented regions. Great gains will be made by increasing research and data sharing in African, Asian, and South American forests.

    Main conclusions: The extensive data and coverage of the ITRDB shows great promise to address macroecological questions. To achieve this, however, we have to overcome the significant gaps in the representativity of the ITRDB. A strategic and organized group effort is required, and we hope the tools and data provided here can guide the efforts to improve this invaluable database.

  • Research Category: International Research Projects; Historical and Retrospective Studies

  • Figures:
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