A model that combines the Stefan/St. Paul equations with a daily snowpack/soil water-balance model was used to investigate the effects of forest cover on times and depths of soil freezing and thawing. The approach was to simulate field experiments reported in the literature for a variety of geographic locations. Three general geographic regions form which data were obtained were interior Alaska, the Lake States, and New England. These results were found in 12 research reports and involve 14 sites in 8 states. The effects of fires and timber harvest were represented in these case studies for forest cover change. While limitations of accurately reproducing the actual site conditions of the original studies were at times severe, insight into the general pattern of response in each situation was gained. The study reinforced the value of modeling to explore, identify and at times, reconcile what seem like contradictions and discrepancies in the literature. The study underscored the difficulty of developing simple predictive rules of thumb when so many variables influence the outcome. Areas of model weakness and needed research are discussed.

John D. Fox, Jr.
Associate Prof. Resource Management
Dept. of Forest Sciences
University of Alaska Fairbanks
P.O. Box 757200
Fairbanks, AK  99709-7200
Phone:	(907) 474-7084
FAX: (907) 474-6184
e-mail:  ffjdf@aurora.alaska.edu