This is an old thread but it should stay static.
I too have found the large variety with dense convolutions growing off of black walnut husks.
No walnut trees around only sugar maple, small shagbark hickories, rosa multiflora, spicebush and a few beech trees.
Usually in the hickory tree dominant woods they grow around the smaller hickories and sometimes on their nuts but don't get that big. But when they grow on the walnut nutshells they are much larger like gigantic. But I wonder if that is enough as a clue because I was finding them mostly next to rosa multiflora.
But my uncle had purchased a truckload of hickory nuts one time long ago and dumped the pile in the woods behind his house after which morels started showing up where they were. But overtime they started vanishing even though there were 40 ft hickory trees growing over top producing their own nuts. However like I said I see that in hickory woods there is a strong chance of them growing.