Volume 46, Issue 2 pp. 355-368
RESEARCH PAPER

The International Tree-Ring Data Bank (ITRDB) revisited: Data availability and global ecological representativity

Shoudong Zhao

Shoudong Zhao

State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China

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Neil Pederson

Neil Pederson

Harvard Forest, Harvard University, Petersham, Massachusetts

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Loïc D'Orangeville

Loïc D'Orangeville

Harvard Forest, Harvard University, Petersham, Massachusetts

Faculty of Forestry and Environmental Management, University of New Brunswick, Fredericton, Canada

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Janneke HilleRisLambers

Janneke HilleRisLambers

Biology Department, University of Washington, Seattle, Washington

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Emery Boose

Emery Boose

Harvard Forest, Harvard University, Petersham, Massachusetts

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Caterina Penone

Caterina Penone

Institute of Plant Sciences, University of Bern, Bern, Switzerland

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Bruce Bauer

Bruce Bauer

National Centers for Environmental Information, National Oceanic and Atmospheric Administration, Asheville, North Carolina

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Yuan Jiang

Yuan Jiang

State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China

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Rubén D. Manzanedo

Corresponding Author

Rubén D. Manzanedo

Harvard Forest, Harvard University, Petersham, Massachusetts

Biology Department, University of Washington, Seattle, Washington

Correspondence

Rubén D. Manzanedo. Harvard Forest, Harvard University. 324 N Main St Petersham MA 01366.

Email: [email protected]

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First published: 05 December 2018
Citations: 154
Editor: Alexandre Antonelli

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: (a) quantify its biases, (b) assess how well it represents global forests, (c) develop tools to identify priority areas to improve its representativity, and d) make available the corrected database.

Location

Worldwide.

Time period

Contributed datasets between 1974 and 2017.

Major taxa studied

Trees.

Methods

We identified and corrected formatting issues in all individual datasets of the ITRDB. We then calculated the representativity of the ITRDB with respect to species, spatial coverage, climatic regions, elevations, need for data update, climatic limitations on growth, vascular plant diversity, and associated animal diversity. 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 represented 81% of the ITRDB and even in well-sampled areas, broadleaves were poorly represented. Our PSI stressed the need to increase the database diversity in terms of broadleaf species and identified poorly represented regions that require scientific attention. 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 show 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.

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