Ruminations on Walnut Trees and Jugulose

Last fall a storm brought half of a black walnut tree down on the power line to the house. The power company came and removed the limbs from the line, but did not remove the limbs.  The pieces were too large for me to move, so they lay where they fell since that time. This picture shows the effects of jugulose, a chemical found in the leaves, roots, and in fact all parts of the black walnut. Ever since I became so interested in plants, the information about how walnut trees inhibited growth of nearby plants has appeared several times a year in horticulture materials I commonly read. However it was not in my personal experience. There are lots of black walnut trees in the edge of the woods surrounding my house as well as several in the area of my greenhouse. There is ample grass, weeds and frequently shrubs growing under these trees, so I was skeptical at least. This cut tree does verify that there is some truth to the jugulose story. Everything around where these leaves and nuts fell is dead and the black dead leaves and nuts show clearly that they are inhibiting the growth of other plants.
This in no way explains why plants can grow easily (it seems) under a living tree, but it does advise against adding walnut leaves to compost or using them for mulch.
My biggest worry with my standing walnut trees involves the nuts. This time of year they are all over the place. Being round, when they fall, they roll off in all directions. I come along and use them for roller skates, an activity that I used to be able to do, but never was very competent at. So, several times a week I pick up the nuts or toss them away into the edge where I do not walk. I have no desire to harvest the nuts for eating, so if you want any, come over here and I will help you pick them up. Just take them. Please. They fall on my fiberglass greenhouse and crack the panels. I am still waiting for one to crack me on the head.
In the mountains I see these huge black walnut trees that are useful in furniture making and other woodwork, but my question is :Why are the trees that live in southeast Alabama such twisted measly specimens? I know of a walnut tree in my grandmother's yard that has been there at least 70 years and it is still a small tree, probably no bigger than 12 inches at breast height (dbh).