Articles, Books and ReportsPlanning Trails with Wildlife in MindTrails & Wildlife Task Force, Colorado State Parks and Hellmund Assoc. 1998 Natural Surface Trails by DesignBy Troy Scott Parker
Trail Construction and Maintenance NotebookUSDA Forest Service — Technology & Development Program2300 Recreation, October 1996. Revised February 1999. 9623-2833-MTDC
Publications on Trail Planning, Design Construction and MaintenanceProfessional Trailbuilders Association
Web LinksArrowhead Trails, Inc.Sahale, LLC - Trail and Bridge Planning, Engineering and Construction - Seattle, WAAmerican TrailsProfessional Trailbuilders AssociationAll of the above are great resources for trail construction, cross-sections, etc.