We have found the following links useful and informative.  Hopefully they will be of interest to you as well.

Forestry Related
School of Environmental and Forest Sciences, College of the Environment
Landscape Management Project, University of Washington
Silviculture Laboratory, University of Washington

College of Forestry, Oregon State University
ORGANON Home Page, Oregon State University

Finnish Forest Research Institute

U.S. Forest Service, Home Page
Pacific Northwest Research, Home Page
Pacific Northwest Research, Westside Silvicultural Options Team, Home Page

U.S. Forest Service, Forest Management Service Center, Forest Vegetation Simulator

Stand and Landscape Visualization
Techniques for Visualizing the Appearance of Timber Harvest Operations, Robert J. McGaughey, USFS, Council on Forest Engineering Paper, 1997
Overview of Visualization Techniques and additional links, Robert J. Mcgaughey, USFS
Sylvan Display Program, University of Missouri
SmartForest, University of Illinois