@Darasama. Please take a moment and update your "Profile" stating your location. City and state are most helpful, but just the USDA zone is better than nothing. Location can be important when asking questions or giving advice.
Maples can be very tricky to grow. I had three beautiful maples in my front yard, and after 8 yrs., two died. No one knows why. They were put in by a well-respected horticulturist and I had one replaced five years ago when the first one died. That replacement died as well. The horticulturist came out several times and tested the soil but could find nothing of importance that would kill the (3) trees. He said many maples simply don't do well in the deep south, though he can't explain why the one tree is still looking healthy. It is probably 20' tall now. He said he would put more maples in but I declined, since I feared they are "northern" types and I would simply lose them again. I am growing native maples in large pots, transplanted pups from wild, but healthy, ones. All of these are growing well. Time will tell.
I personally would not remove that (rooted) mulch.