The Unique Base of a Hill Tree

This tree is almost 20m high and is about 45 years old , after my parent abandoned the Farm.

Most of the hill trees anchor deeply into the soil in order to survive, which means larger base trunk and deep foundation. But this tree has smaller trunk base but large root system to stabilise the foundation. So it shows that Nature tried various methods to survive and the least fit ones will disappear along our long history of life.

Of course, the change of surrounding, such as erosion of soil would also cause this scenario. But it occupies a lot of the land, shall I cut away the roots or cut down the tree? 
It is too near at my proposed little house.