Local landscaper came by and had a few suggestions for our back lawn. They suggest putting in a flower garden with shrubs, BB bushes, etc in the area around and in front of the oak tree. They would build up that area with topsoil and very small retaining wall, plant the bushes then add mulch. Seems like a good idea. Their concern is that if we go for just grass around the oak, it will eventually erode away again due to the oak sucking down so many nutrients away from the grass. Seems to make sense.