USDA Forest Service

Pacific Southwest Research Station
Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Ecosystem Processes

Sierra Nevada Ecosystems

The Impact of the Neogene (late Tertiary) on Biogeography and Evolution of Conifers in Western North America

Study Plan

The Research

collecting fossils The Tertiary is a period of key importance in the evolution of modern conifers and the establishment of modern ecological and biogeographic associations in western North America. Major global climate changes and significant phases of orogeny and crustal extension and collapse catalyzed key reorganizations in the biogeography of conifers. Many modern conifer species of western North America first appear in mid-Tertiary macrofossil records. Abundant exposure of Tertiary rocks has enabled a large body of paleobotanical literature to develop. Much of the emphasis of this work, however, has been taxonomic, focusing on morphology, and climatic implications. Little synthesis of Tertiary with Quaternary methods and interpretations has occurred, although the development of ideas and tools from Quaternary paleoclimatology and paleoecology lends itself to Tertiary analysis. I focus on bringing Quaternary perspectives to existing Tertiary records to analyze biogeographic history and population-genetic/evolutionary histories of modern conifers, especially Pinus. These records can be compared to, and inform the interpretation of, new research by others in conifer molecular phylogeny.


blue arrrow Evaluate the effects of climates and geomorphologic development during the Miocene and Pliocene on migration, population expansion and contraction, and geographic distributions of western North American conifers.

blue arrrow Assess biogeographic impacts on longterm evolution in these taxa and compare to interpretations from molecular and other genetic studies.

blue arrrow Combine information on Quaternary paleoclimatology and biogeography with Tertiary records and interpretation to develop more seamless trans-Cenozoic (Tertiary:Quaternary) perspectives on conifer history and evolution.

Application of Research Results

map of the Sierra Nevada Ecoregion
Western North America

Lead Scientists/Collaborators

1) Millar, C.I 2) Erwin, D. and 2) Schorn, H.

1) USDA Forest Service, PSW Research Station
Sierra Nevada Research Center
800 Buchanan St., Albany, CA 94706 USA
ph: 510-559-6300

2) Museum of Paleontology, University of California, Berkeley, CA

Publications and Reports
  • Millar, C.I. 1998. Early evolution of pines. Pages 69-94 in D.M. Richardson (ed.), Ecology and Biogeography of Pinus, Cambridge University Press.
  • Millar, C.I. 1996. Tertiary vegetation history. Pages 71-124 in Sierra Nevada Ecosystem Project: Final Report to Congress, Volume II. Assessments and Scientific Basis for Management Options. Wildland Resources Center Report No. 36, University of California, Davis CA.
Last Modified: Aug 29, 2016 10:57:04 AM