Our farm is overloaded with black walnuts. Seems some years they are great, others aren't. Since they line the driveway (almost a mile long) I haven't noticed the producetion. I've had garbage cans filled with them in the past. The one thing I did find out are they are very hard to get the meat out of -- tried everything. ONE THING TO REMEMBER, if you have horses keep them away from the trees, sawdust or anything else, if not, you will have a very sick horse with problems with their feet.
Linda