In building an understanding of the Northern Hardwood Forest there are many components, they are all dynamic and should be understood.

The canopy of any forest is vital. Depending on the region of the USA or the world for that matter, the canopy takes on different characteristics. But, all forests when comprised of native species have the same components. 

Under the canopy is the "Understory" and "Scrubs." These species do well in some degree of shade. They provide living quarters for animals and birds. 

There are some interesting understory indicator species for the Northern Hardwood Forest:

Striped Maple
Hobblebush
Nannyberry
Mountain Laurel
Canada Honeysuckle

I will look at each one here.