So I would think that Jax has the upper hand on this one once Maokai roots him he can stun him and pounce onto Maokai and just destroy him. On the other hand Maokai can ult then jump in and take a ton of dmg and give a ton with his ult a q. So what do you have to say would Jac win the 1v1 or Maokai?
It's dependent on builds.
If Jax has something like 
then I dont really see maokai winning that fight
I've been on both ends of this. Really depends on player skill in the end.
maokai is one of the worst 1v1 champions in the game after early game.
tank mao or ap based?
Who would win in a 1v1: Jax or Maokai
Jax is one of the best duelists in the entire game, if not the best due to his capacity to easily beat a range of otherwise better duelists with his BS helicopter mode.
Maokai is not. Maokai is an amazing team-fighter and has godly ganks from the jungle, but his job in 1v1 situations is mostly stalling for time, or trying to bog down an opponent while his team can take advantage of that.
In a thunderdome setting: Maokai doesn't stand much of a chance vs. Jax. Not many champions really do (outside of pre 6 where Jax is actually kind of terrible). Jax's lore isn't to far off from the shenanigans he can pull in-game.
If Jax has enough attacks speed and some sort of sustain, he can win, even if he get's CC'd because he can just jump back in combat. And use counter strike to stun him.
But if Jax has neither, then Maokai can win.
define win
if you mean destroy the nexus jax would win. I don't care to speculate on the dueling, jax would eventually win that if not early
