Q. I have a Modesto ash tree in my front yard.  I have had it for 12 years, so it is a big tree.  I am having a problem with its roots.  They are coming up through the grass.  Are those top roots?  They are ruining my yard.  What can I do for this problem?  I love the tree but not the roots. Surface roots of large tree. My picture, not the readers. A. This can be a problem with ash tree particularly if they are not watered deeply and were planted in a lawn. Lawns are typically watered with shallow irrigations because most lawn roots grow in the top 12 inches of soil. Since the tree is also growing in the lawn and receiving the same irrigation water as the lawn they will be in competition with each other for this water.             Maybe you mean tap roots and not top roots? Tap roots by definition do not grow on the surface of the soil. Trees with tap roots in nature seldom develop true tap roots once they have been replanted or transplanted into landscapes.             To develop tap roots trees need deep waterings or have deeper water available to them for their roots to grow into. In our desert environment most irrigations are shallow since water is expensive and we try to conserve as much as we can. In some cases you can remove a few surface roots without compromising the tree. You could explore this option.             Trees use their roots for taking up water and nutrients as well as stabilizing itself in the soil to keep it from blowing over. Tree canopies act like sails. If too many roots are removed, obviously this could result in the tree blowing over in heavy winds.             If you are removing more than one or two roots then you should consult with a certified arborist about the potential for blowover.