Long passages of Masechet Succah discuss the requirements for the Schach and the walls but I don't find a discussion of what constitutes the floor.
I can think of two related Nafka Minot (Halachic applications):
Many Haredim in Israel that live on 2-5 floor make their Succos on "temporary balconies" - supported by metal pillars and the floor made of metallic railings. How far should those railings be one from another to constitute a usable floor for a Succah?
The Mishnah says "העושה סוכתו בראש האילן", however, it does not elaborate where it requires a steady floor or the branches suffice. Let's stick with the latter - I think that 10'-15' branch is enough for one to eat comfortably on a tree. How strong and dense should the branches be to constitute a Succah's floor?
Both the Schach and the walls are measured from the Succah's floor. Also Gemmorah mentions אצטבא that is used to lessen the height under 20 Ama. How strong and dense should the floor be to constitute a Succah's floor for that measurement? For example with the tree - if the Schach is 25 Ama high, how strong and dense should the branches be over 5 Ama from the ground to measure the Schach from it?