American Hophornbeam Tree, Also known as ironwood.
While hiking on Rattlesnake Island a few weeks ago, I came across this really interesting and beautiful tree that was flowering. I could not figure out what it was, but UNH Cooperative Extension did.
If I am not mistaken, the bridge between Birch and Steamboat island is made from this type of tree.
http://mlp.arboretum.purdue.edu/webo...1#.WXovaoTyuUl