Can I Put Soil Over My Maple Tree Roots?

Surface Root Structures

• Trees' roots do not mimic the trees' branch structures, a common misconception, according to the University of Minnesota Extension. In most trees, 90 percent of the roots are within the first 3 feet of soil and between 50 and 75 percent of the feeder roots are within the top foot. Maples are among the trees particularly known for their very shallow feeder roots; some species, like the red and sugar maples, can raise sidewalks if planted along the street.

Maples and Lawn Mowers

• Because maple feeder roots grow so close to the surface and because softwood species, in particular, are susceptible to mechanical damage, special care must be taken to protect those roots. Turf does not grow well under maples, nor should it be planted, according to Clemson University Cooperative Extension. Mowing over these roots could not only severely damage the tree but could damage an expensive lawnmower.

To Soil or Not To Soil

• According to the University of Minnesota Extension, soil should never be placed over shallow roots because it can kill the tree. Surface roots are adapted to be above most of the soil, not below it. Soil can suffocate the roots, hold too much moisture or simply wash away if irrigation is required -- as is the case with many maples. The university warns not to cover roots with soil even in an attempt to change the land's grade. With shallow roots, it is best to leave the grade as it is, even if it's not ideal. Also avoid impermeable plastics, which reduce air and water exchange.

Alternatives To Soil

• Applying 3 to 4 inches of organic mulch is the best option to cover and help protect the shallow root system of maples. Mulches conserve moisture, keep soil temperatures cool and protect the base of the tree from physical damage. Mulches also allow for well-drained soil -- a must for healthy maple growth. Gardening stores usually also carry permeable materials that allow for air and water exchange, which are acceptable alternatives.