New data from tree rings from 500 sites around the world is now available from the Commerce Department's National Oceanic and Atmospheric Administration. These data are important because they provide climate scientists and resource managers with records of past climatic variability extending back thousands of years.

The data, available from the International Tree-Ring Data Bank at the World Data Center for Paleoclimatology in Boulder, Colo., were contributed by Fritz Schweingruber and colleagues at the Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL-Birmensdorf). The data include tree ring width and wood density measurements, and site chronologies. The data represent the largest data contribution in the history of the International Tree-Ring Data Bank.

Schweingruber submitted all of his data files to the World Data Center for Paleoclimatology to be made publicly available in preparation for his retirement. The World Data Center for Paleoclimatology is housed at NOAA's National Geophysical Data Center. One of the most significant features of this collection is the contribution it makes to the coverage of tree-ring data in high latitude Northern Hemisphere forests, particularly across Fenno-Scandinavia and Siberia.

Paleoclimatic data are a valuable complement to the much shorter time series derived from instruments and satellites. Paleoclimatic data are used to describe the full range of climate variability, to identify and understand the causes of this climatic variability, to evaluate and improve predictive climate models, and to improve the ability to separate human-induced climate change from natural climate variability. NOAA's paleoclimatology holdings include data from sources such as tree rings, corals, ice cores and sediments.

NOAA's National Geophysical Data Center is part of the National Environmental Satellite, Data, and Information Service, the nation's primary source of space-based meteorological and climate data. NESDIS operates the nation's environmental satellites, which are used for weather forecasting, climate monitoring, and other environmental applications such as fire detection, ozone monitoring, and sea surface temperature measurements. NESDIS also operates three data centers, which house global data bases in climatology, oceanography, solid earth geophysics, marine geology and geophysics, solar-terrestrial physics and paleoclimatology.

To learn more about NESDIS, please visit http://www.nesdis.noaa.gov.

To access the tree-ring data, please visit: http://www.ngdc.noaa.gov/paleo/treering-wsl.html.