They are quite rare as far north as I live though I do know one classic old-farm fence row planting that did quite well in NW Michigan; near enough to Lake Michigan that it could be either Zone 5 or maybe even Zone 6, most years.
So I haven't pursued this idea .... but there is now finally a market for the "monkey balls". It seems they are in demand in the cosmetics industry as an ingredient for some sort of moisturizer or some other product. So there is a purchaser in Iowa who buys them in by the truck-load. As in semi-Truck load.
I heard about it on NPR and the details are available via Google and enough keywords from those two paragraphs there.
Sounds like easy money to me, in areas where they are a common tree. I like raking money off the ground as I am a professional acorn dealer. But since it requires being outdoors and a minimum of muscle movement, I think the story I read when I looked into this is that mostly the Amish are supplying this new market, as most people these days are quite afraid of moving a muscle in the scary Outdoors.
