Avoid tree instability issues when having landscaping done or building a new house. All too often people bring in topsoil or fill and bury the trunk flare of existing trees which will result in a stem-girdling root which destabilizes the tree. You should always be able to see the sweeping radius from the tree trunk to the beginning of the root system. If the tree appears to grow straight out of the ground after backfilling then you have covered the trunk flare and are at risk for it to die. As much as I like to come out and remove dead trees for you lets not induce the death onto good trees we want to keep.
Removing the root, and the fill, dries the root crown and restores the tree to a safer condition.