Tree Matters - Site for The Dendrologist, a quarterly magazine. Also contains tree tips and a record of the dates of upcoming dendrology events in the UK.
Forest Biology and Dendrology at Virginia Tech - Information about courses, trees, and forest biology. Includes fact sheets on over 450 species of trees.
The Ancient Bristlecone Pine - Dedicated to the oldest-known living tree, growing in the White Mountains in east central California. Information about the location, dendrochronology, photo gallery, and bibliography.
Silvics of North America - Compendium of research papers describing the characteristics and distribution of important broadleaf and coniferous forest trees of the United States and Canada, plus many of the native and naturalized trees of Mexico, the Caribbean Islands, and Hawaii. Compiled over several decades by USDA Forest Service scientists.
The American Woods - Wood sections of 350 North American trees from the 14-volume book The American Woods, published between 1888 and 1910 by Romeyn Beck Hough.