Lock all Tree mutations behind infusions

[Decarcassor]

I'm not a fan of locking too many mutations behind infusions. I also don't find trees too difficult to grow the way I want them. Sure they'll mutate once in a while but they usualy bear a lot of seeds and are quite easy to make immortal due to high genome anyway. Also maybe the stabilizer gene might help ?

There is just a lot of mutant trees. Probably a bit too many for a single seed type.