Looking in the woods I see clusters of white flowers standing out against the grays and dark browns that the early spring wood brings. At first glance they may seem to be all alike. But after taking a closer look, you'll notice the flowers are actually very different. In Wisconsin we have Cherry trees and Service Berry trees in full bloom right now.
Service Berry/June Berry trees belong to the genus Amelanchier. When viewing from a distance they appear very white, maybe the fact that the petals are droopy, therefore covering the yellow center. If you want to key out your particular tree to the species level you would have to look at the number of lateral veins running through the underside of the leaf. 8-10 pair (Inland Serviceberry); 12-17 pair (Juneberry)
Take a walk outside and look around, you might surprise yourself by seeing something for the first time, something overlooked because it is so common.