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Archival photographs show no climate-induced changes in woody vegetation in the Sudan, 1943–1994*


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    Many of the data for this paper are in classified intelligence archives. As a consequence, the options for evaluating the paper and for ensuring that other scientists can reproduce the analysis are constrained. Publication of this paper in Global Change Biology is intended to illustrate the potential use of, and stimulate discussion on the role of, classified data in the open scientific literature. Limitations on access to the data make it impossible for the journal's usual review process to assess all aspects of data quality, selection, or interpretation.

William H. Schlesinger, fax +1-919-660-7425, e-mail


An archive of satellite and aircraft photographs of the western Sudan showed no longterm (1943–1994) trends in the abundance of trees despite several decades of recent drought in this region. These data extend the extant historical record of vegetation change in the African Sahel, where recent fluctuations in vegetation greenness have been monitored with the NOAA Advanced Very High Resolution Radiometer since 1980. Despite substantial population turnover, woody vegetation is not yet indicative of the recent climate changes in this region.

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