Here's an unusual understory tree.  American Mountain Ash features a beautiful, rounded crown and lovely lace-like summer blooms on the tips of the branches just as the leaves come out. 
 
American Mountain Ash is a larval host to the Canada Tiger Swallowtail butterfly and the White Spring Moth and other moth species.
 
Red berry-like fruits emerge in September and would hang on through winter except they're usually devoured by birds -- look for Robins, Baltimore Orioles, Blue Jays and Cedar Waxwings. 
 
Fall color is a golden orange, although the leaves on Mountain Ash tend to drop early, easier for the birds to drop in and grab the fruits.
 
Note: Mountain Ash is a member of the Rose family and thus is not susceptible to the Emerald Ash Borer.    
 
Fun fact: The fruits can be eaten raw or cooked and generally turn sweeter after the first frost.