I thought the squirrels had eaten all of them.
UW-Green Bay herbarium web page, resemble a leaf bud - near the end of the twigs.
After some googling, I learned that the American hazelnut is a dominent (or co-dominent) shrub of the maple-basswood forests of Wisconsin. The leaves, twigs and catkins are browsed by deer (and moose), the nuts by small mammals, Ruffed Grouse and deer, and the bark by beaver.
American hazelnut is a common understory associate of smooth sumac, chokecherry, arrowwood, dogwood, raspberry, eastern hophornbeam and shagbark hickory.
If you like your coffee flavored, the hazelnut syrup comes from the European cousin - filberts, the commercially cultivated nuts which are also used as fillers in cans of mixed nuts.
Hazelnut can reproduce sexually (the nuts) and asexually (from woody rhizomes just below the surface). Underground roots and rhizomes can survive fire when the humus is moist.