Dr. Stahle was a speaker at a Mayor Lori DeLuca Symposiums

Dr. David Stahle

Distinguished Professor, Department of Geosciences - University of Arkansas at Fayetteville

Dr. Stahle's research interests include all aspects of dendrochronology (tree-ring dating), particularly climate change and the proxy evidence for past variation in the El Nino/Southern Oscillation and other large scale atmospheric circulations.  He has developed GIS-based predictive models for the location of ancient forests, and is conducting active research in the United States, Mexico and Africa. Dr. Stahle's research is funded by NOAA , NSF , NPS and the USGS and he has published in a variety of journals including, Science, Nature, Journal of Climate and Bulletin of the American Meteorological Society. Dr. Stahle has taught courses in Physical Geography and Conservation of Natural Resources.

He has earned the following degrees:  Ph.D., Arizona State University, Geography 1990; M.A., University of Arkansas, Geography 1978;  B.A., University of Arizona, Anthropology, 1973.

Dr. Stahle has published many studies including Tree Ring Dating for Post Oak Trees of the Southcentral U.S.  He has also ring dated the trees that comprise historical log cabins.  He also is a staff member at the Tree Ring Laboratory and Cross Timbers Consortium mentioned below.

The Tree-Ring Laboratory (TRL) was established in 1979 and concentrates on the development of exactly-dated annual ring-width chronologies from ancient forests worldwide. Tree-ring chronologies provide unique archives of environmental history and have many inter-disciplinary applications. These tree-ring chronologies are based on small core samples extracted non-destructively from living trees and cross-sections cut from dead logs. We specialize in the reconstruction of past climate and stream flow, the socioeconomic impacts of past climatic extremes, the dating of historic structures, and the identification and mapping of ancient forests. We conduct research in the southeastern United States, the southern Great Plains, California, Mexico, and southern Africa. The TRL is active in the conservation of ancient forests, and has assisted the preservation of ancient forest remnants in the cypress-tupelo forests of the South, the oak-hickory forests of the central United States, the blue oak and conifer woodlands of California, and the conifer forests of Mexico.  More TRL publications can be found here.

The TRL helped establish the Ancient Cross Timbers Consortium which unites universities, federal and state agencies, conservation organizations, and private landowners for research, education, and conservation efforts in these widespread ancient forest remnants still found on the margins of the southern Great Plains.

November 2001

PBS Television's "Scientific American Frontiers" with guest Dr. David Stahle

(excerpts)

Tree rings are shedding new light on several historical mysteries. White spruce trees from Alaska indicate that the coldest summer in 400 years occurred in 1783. This unusual cold was probably brought on by the 1783 eruption of the Laki volcano in Iceland, and appears to have been responsible for widespread starvation and population decline among the Inuit during the "Time summer Did Not Come" (Gordon Jacoby and others, Quaternary Science Reviews, 1999).

The 16th century "megadrought" across North America (roughly extending from 1540-1590) has been linked with the disappearance of the English Lost Colony of Roanoke Island (1587), the abandonment of the Spanish colony of Santa Elena at Parris Island, South Carolina (1587), the abandonment of Tewa, Keres, and other Puebloan villages in New Mexico (mid-16th century), and with two of the greatest human mortality events in New World history....the cocoliztli epidemics of 1545 and 1576 in Mexico when millions died from hemorrhagic fevers possibly associated with a rodent vector leveraged by extreme drought conditions (Stahle and others, Eos, Transactions of the American Geophysical Union, March 21, 2000).

Tree-ring dating is the most accurate and precise dating method in geochronology, capable of dating determinations to the season of a specific calendar year. 

Ancient forests with giant trees get a good deal of press, deservedly so, but not the dwarfed, gnarly, old-growth trees found on harsh sites throughout the United States and really around the world. Our public vision of old growth tends to perceive redwoods or other huge trees of temperate rainforests, and not the stubby, stunted, and most ancient of trees such as the bristlecone pine, the blue oaks of the California foothills, or the craggy chestnut oak still found along exposed positions of the Blue Ridge Parkway. Out of ignorance for the true antiquity of these sorts of super senescent trees, they continue to be destroyed for very mundane reasons. You can see an example of this type of low-stature noncommercial woodland at our website on the Ancient Cross Timbers in the south-central USA (http://www.uark.edu/xtimber).

I believe that if people realized that many trees in noncommercial woodlands were old at the birth of American democracy, then they might very well have a higher opinion of these austere survivors and the intricate natural histories they preserve in their centuries-long tree-ring series. If we realized that these ancient woodlands on stressful sites scattered throughout the United States were indeed one part of the complex vegetation mosaic that made up the presettlement natural landscape, then we might think twice about scraping away these authentic Americans for chip mills, parking lots, or new homes landscaped with still more Bermuda grass and ornamental pear trees.