Northern Arizona University home
Home Research Teaching Students Laboratory of Paleontology Publications Gallery

Professor of
Quaternary &


Swmp Lake cores

Much of our fieldwork consists of taking sediment cores from lakes and wetlands. This figure shows individual core segments taken from Swamp Lake in Yosemite National Park, a particularly deep lake, with laminated sediments, often corresponding to deposition during individual years. Sediments like these allow paleoecologists to reconstruct vegetation (using pollen and plant remains), fire (identifying charcoal particles), and many other aspects of environments in the past.

I cannot remember a time when I was not interested in, and moved by, the natural world. As a youth, I spend much of my spare time exploring the mountains in my home state of Colorado. In college I was influenced by early naturalists such as John Muir and Henry David Thoreau, so much so that I chose to work at different times in areas intimately known by both of these men. For me, the beauty of the study of my chosen field – paleoecology – lies in our ability to understand ecosystem change in a long-term context.

Here at NAU, my primary research focus has been to understand the way that climate change and stand disturbance regimes such as fire, affect vegetation over long time scales. Pursuing this focus has led me and my students to many interesting places, as you will see on this Web site.

  • B.A. 1974 University of Colorado, Environmental Biology
  • M.S. 1979 University of Maine, Quaternary Paleoecology
  • Ph.D. 1987 University of Arizona, Geology (Quaternary & Environmental Sciences)
Research interests
  • Disturbance ecology, primarily the effect of fire and insect infestation on former plant communities
  • Paleoecology and climate history of plant communities
  • Global change issues, especially as they relate to human activities in forested ecosystems
Research projects
  • Biogeography and disturbance history of mixed conifer forests of the Sierra Nevada, California
  • Vegetation, climate and disturbance histories of the Southern Rockies and Colorado Plateau, southern and coastal California, southeast Alaska, the Southwestern Deserts, Argentina, and Spain
  • Inter-annual variation in climate and vegetation as recorded in annually laminated sediments in California and Colorado