Possibly doesn’t count, but some years back, I implemented a CESIL interpreter (at least this part is retro!) in BASIC and gave it some graphical xmas tree controls…
There’s very famous early educational program for the Beeb called “Granny’s Garden” - that features trees, including a guess the magic tree game: here’s clip from RetroKit:
On the 25th of March 2012, I took this BBC Micro to the Beeb@30 event which celebrated its 30th birthday. I used this BBC Micro to demonstrate the educational game Granny’s Garden being run from the Acorn Archimedes A410/1 which was configured as an Econet server.
(I think the game might be famous in part because it was so widely used in schools, and features in so many people’s memories, and in part because it’s still not widely distributed, as the owner still chases down any online copies. Video of the game here.)
Nice info in the footnote to that, explaining how a 1973 poem was dug up and the author contacted electronically. “Readers of BYTE who own personal computers with an RS-232 interface will soon be able to sign up for private services equivalent to the electronic mail functions used by Henry and Guy in arranging this over the Arpanet”