Ah, but Old Man Willow wasn't the only tree to grasp at hobbits, according to Merry. And I doubt the entire Old Forest was composed of willows.
A mallorn? I never thought of that. It's certainly spreading enough to support a flet, although it has no main trunk. I mean, the way live oaks grow is to split into multiple branches about 10 (or fewer) feet from the ground; there's no leader left. The Century Tree has at least 5 main branches at that split. They almost rival the truck in size, and it's already enormous. It could support a very large-size flet, although not very far from the ground. The entire tree is no taller than 40 feet and probably closer to 30.
It would be awesome to actually build a flet in it! Barring the University's protests, though, I might be attacked by some cadets. Something tells me they wouldn't take kindly to defacing a landmark.
The Century Tree isn't just a big tree with a name. (Albeit an appropriate name - it's thought to have been planted in 1898.) The tradition is that if you walk under it with someone of the other gender, you're going to marry that person. For that reason, Corps cadets give it a wide berth on ordinary occasions. But on Saturdays, especially on game days, I've seen many proposals take place at that bench. And after the girl accepts, there's a saber arch for the couple! Very cool.
So the building of a flet in the Century Tree is fraught with dangers - physical and matrimonial.
Oh, I found another picture:
You don't need a flet to study in it!