I'm not sure why but my Illinois ever bearing was doing great one day then totally dead another. I'm still not sure why. The soil was moist so it didn't dry it out. My guess was maybe root rot or sooty canker disease which is a fungus that can kill a tree if it affects its trunk. But I'm not really sure. I had a layer of pine and bark on the top layer as mulch.
RIP Mulberry tree... it's sad to see you go.