Bradford Pear tree flower

you see these everywhere in the spring; an unsafe tree that splits easily weakest branch structure; seldom last more than 20 years; The problem is that these trees are in fact not sterile. No two Bradford pears will ever reproduce among themselves, but they do cross pollinate with every other pear tree out there, because of the cross pollination problem, pear trees have now proliferated exponentially across our environment. And, to make matters worse, the evil offspring has reverted to the ancient Chinese Callery pears which form impenetrable thorny thickets that choke out the life out of pines, dogwoods, maples, redbuds, oaks, hickories, etc.