The following are a few of my favourite web sites related to trail and dry-stone construction.
Track and Trail Management Services
First and second CBC News reports on Russell dry stone bridge construction.
Final CBC News report on Russell bridge.
Dry Stone Walling Association of Great Britain.
Dry Stone Conservancy, USA.
Professional Trail Builders Association, USA.
Blog of master dry-stone waller Norman Haddow.
American Conservation Experience.
U.S.trail and bridge construction company.
Icelandic masonry site.
U.S. wood and steel bridge company.