Illinois Plant Information Network
USDA Plants Interactive ID Keys
U.S. Forest Service - Silvics of North America (online version)
Software for Tree Ring Analysis (Dendrochronology)
Conversion between Lat/Long and UTM
Dr. Loretta Battaglia, Southern Illinois University Carbondale, USA
Dr. Rick Essner, Southern Illinois University Edwardsville, USA
Dr. Dan Faith, Australian Museum, Australia
Brian Ickes, USGS Upper Midwest Environmental Research Center, USA
Dr. Jari Oksanen, University of Oulu, Finland
Dr. Dave Roberts, Montana State University, USA