• A Debt to the Future: Scientific Achievements of the Desert Laboratory, Tumamoc Hill, Tucson, Arizona

      Bowers, Janice E.; U.S. Geological Survey (University of Arizona (Tucson, AZ), 1990)
      In 1903 the Carnegie Institution of Washington established a Desert Laboratory on Tumamoc Hill, Tucson, Arizona. For the next thirty -seven years the Desert Laboratory was the site of pioneering research into the biology and ecology of desert plants and animals. The more than sixty scientists who worked on Tumamoc Hill published some 350 papers and books based on research there. William A. Cannon and Volney M. Spalding share credit for successfully launching the new facility. Daniel T. Mac - Dougal, who became the first director in 1906, hired an enthusiastic, able staff and recruited many visiting scientists. His untiring promotional efforts gave the laboratory a national reputation, and when he transferred his research projects to a second laboratory at Carmel, California, the Desert Laboratory entered a nine -year decline. Promotion of Forrest Shreve to head the laboratory in 1928 brought about a renewed focus on the ecology of desert plants. The Carnegie Institution closed the facility in 1940, ostensibly because of the depression and consequent financial cutbacks, but actually because institution administrators no longer found it worthwhile to support descriptive ecological research.
    • A Debt to the Past: Long-term and Current Plant Research at Tumamoc Hill in Tucson, Arizona

      Webb, Robert H.; Turner, Raymond M.; U.S. Geological Survey (University of Arizona (Tucson, AZ), 2010-12)
    • Reproductive Potential and Minimum Reproductive Size of Ferocactus wislizeni (Cactaceae)

      Bowers, Janice E.; U.S. Geological Survey (University of Arizona (Tucson, AZ), 1998-06)
    • Some Geometric Constraints on Ring-Width Trend

      Phipps, Richard L.; U.S. Geological Survey (Tree-Ring Society, 2005)
      Simulations of tree rings from trees of undisturbed forest sites are used to describe natural, long-term width trends. Ring-width trends of canopy-sized white oak are simulated from regressions of BAI (ring area) data of real trees. Examples are given of a tree from a typical re-growth forest in Illinois and of a more slowly growing tree from an old-growth forest in Kentucky. The long-term width trend was simulated as being toward constant ring width regardless of growth rate of the tree. Conditions by which either increasing or decreasing ring-width trends could be simulated from the same linear BAI trend are examined. I conclude that curvilinear width trends, either increasing or decreasing, represent width adjustments to changes in growth rate (BAI trend) after which the width trend stabilizes to a near-constant value. Interpretation of ring-width trends of trees from undisturbed stands may be useful in assessing stand disturbance history.
    • Vegetative Key for Identification of the Woody Legumes of the Sonoran Desert Region

      Turner, Raymond M.; Busman, Caryl L.; U.S. Geological Survey; University of Arizona (University of Arizona (Tucson, AZ), 1985)