So mark this up to one of those things I never knew.
When we moved our horses to Valboa Farm, we noticed these two trees with these big spiny pods - as in baseball/softball size - hanging from the branches. I had no idea what they were. Kind of a freak of nature looking things. And they are sharp spines!
Finally Madison remembered to ask Val. They are chestnuts!
I guess as they ripen, the pods burst open. And the nuts fall out.
Here you can see closed pods, fully opened pods and one that still has nuts in it.
There are 3-5 nuts in each pod and they are pretty big! I've since learned that you need two trees for good fertilization of the nuts or they will be very immature. I haven't roasted them.