Boreal Forest Network
http://www.borealnet.org/
The North American affiliate of the Taiga Recue Network, focussing on the boreal forests of Canada and Alaska. Useful information and beautiful design.
Forest Action Network
http://www.fanweb.org/
Recommended Site. Originating in BC, Canada, the FAN now comprises a network of over 22 groups and 500 activists across North America and Europe. Their tactics range from mapping and research to direct action, and they also work closely with indigenous nations. A provocative and informative web site, especially the "Patrick Moore is a Big Fat Liar" page, which is truly a work of brilliance...
Forest Conservation Portal
http://forests.org/
News, action alerts, and information on forest issues around the world - over 15,000 articles! - plus a Forest Conservation News e-mail list, and a massive, reviewed directory of forest, rainforest and biodiversity web sites.
Global Forest Policy
http://www.iisd.ca/forestry/forest.html
A project of the the International Institute for Sustainable Development (IISD). Records of ongoing intergovernmental negotiations.
Taiga Rescue Network
http://www.taigarescue.org/
"An international network of Non-Governmental Organisations, Indigenous Peoples and Nations working for the protection and sustainable use of the Boreal Forests." This Sweden-based organization offers information on boreal forest ecology and biodiversity, the cultures of the boreal regions, threats faced by boreal forests worldwide, and more.
The Tree
http://www.the-tree.org.uk
A large and complex UK-based site dealing with forest ecology and conservation, sustainable forestry, a guide to British trees, forest folklore and mythology, eco-spirituality, and related topics. Some of the lore is a little dubious -- for example, Robert Graves's pseudo-Celtic tree calendar puts in an appearance -- but there's still a lot of interesting material here.
The WWW Virtual Library: Forestry
http://www.metla.fi/info/vlib/Forestry/
The Virtual Library Project is the oldest catalogue of the web, and was actually begun by the inventor of the web itself, Tim Berners-Lee. It is compiled by volunteers, not unlike the Open Directory Project, but unlike that one it has stringent quality standards and you have to be a recognized expert in a field to be able to maintain a section of it. This section is maintained by Metsãntutkimuslaitos, the Finnish Forest Research Institute.