I’ve never had any tatami mat, but cutting some banana trees back today made me wonder...hmm. These are soaking wet naturally. Would be a huge mess, but probably fun.
Thinking ahead since you guys won’t let me try to forget about this beast for a few more months.
FWIW, I've cut both tatami mats for tameshigiri, and banana trees in Asia when I was there.
I've cut tatami rolls with a katana for tameshigiri, as well as a Chinese jian, dao and Shuang Shao Jian to satisfy my curiosity about the comparative cutting ability of the different sword types. All the swords were shaving sharp.
The banana trees were chopped with a 24" Tramontina machete, that was sharpish. Sharp enough to cut, but not sharp enough for a smooth shave.
For equivalent diameter, the tatami is definitely harder to cut, and quite a bit more intolerant of off angle cuts (i.e. if the blade angle is off, the machete still bites deep into the banana tree, where poor blade angle won't bite as deep in a tatami roll).
P.S.
Some folks are downright terrifying with a machete in their hands, to the point after just a few swings, the general consensus is, "Uh, here, let me take that. I think the rest of us are in greater danger than any vines, plants and brush in our way".