Question about Black Walnut Trees

We have 3 Black Walnut trees on our property. The one in the front is about 25 years old and drops a temendous amount of nuts in fall. The others in the back are about 15-20 years old and have in the past dropped nuts but the last couple of years they have not. Why would one of our trees have nuts and the other 2 do not? It was a very dry summer here and the tree with nuts is dropping them kind of early but we've checked the trees in the back and do not even see a nut on either tree. If anyone can give us an answer it would be greatly appreciated. Also, if we should decide to remove the tree from the front, (it's a terrible mess to clean up every day each fall on our patio and driveway and we're not getting any younger!) would we be able to plant another tree in that same spot or would having had a Walnut tree there harm another type of tree?

i do not have an answer to your question, but i do have a question for you. i am in northwestern il. just south of monroe wi. i have a 3 acre dairy pasture that i am working to naturalize and someone gave me some walnuts to plant. i'm wondering if you easily get seedlings sprouting from the dropped walnuts. if not i'll search for more info to get them to germinate but perhaps just "stepping" them into the ground will get me seedlings for next summer. i can tell you that we were hit with the drought also and many of our 4 to 5 yr old trees were stressed and are coloring and dropping leaves early this year. perhaps the area was dryer or sunnier in the heat this summer and caused the trees in back not to set nuts?