Guys please help me out here

Imposible to say what tree it is unless you  have a time machine

and root probably has nothing to do with dead tree stump.

What other stuff is growing nearby etc as roots go along way

Thank you very much for helping!!!

There is about 6 meters from where I found the bulge a big white barked tree in my neighbors garden (see attached pic).

Also I believe where I live used to be a forest before the house was built 50 years ago so it could be there are lots of roots in the ground.

I also have a flower bed which I regularly water around the old trunk

I am getting worried, I just saw 2 more places where the floor is raised!

Thank you for your help!