When I lived in Berkeley, I exchanged fruits and herbs with Forage Oakland. From one exchange, I received nocino - an Italian liquer - made from unripe walnuts from Delaware Street for nocino I made from a Parker Street walnut tree growing in the sidewalk. I am an Eat Street Trees! advocate - a program of localecology.org that promotes the planting of street trees that produce fruits for human consumption. Although I did not eat the walnuts, I did drink their extract. It's an acquired taste (read: bitter, medicinal) and best served chilled and on ice.
The recipe I used was published by the Hammon Company but the website no longer works. Here's a similar, simple nocino recipe from Simply Recipe. After a few months of steeping, I brought the nocino to a party where a friend of Italian heritage recommended a longer steeping with slices of lemon. Here's an image of a finished product.
Question: Have you ever eaten fruit from a street or park tree? If yes, what fruit?