Published on 08/19/98

Don't Stump Your Landscape

Tree removal is never fun and neat. The passing of a large tree brings you to think first about cleaning up the stem and branches. But what about the stump? Stumps can be massive in a big tree.

A large tree will have a stump with many large roots growing out into the soil. You can cut the surface wood away, but the entire woody root system remains.

As wood decays in large stumps and roots, the soil may subside, or holes may develop in your landscape. Sometimes animals use these subterranean homes. Stumps are safety and aesthetic concerns.

Traditionally, removing a stump has meant digging and cutting, then repeating, until you or the stump gives up. Some have used explosive charges to free the stump from the soil.

Other people try to burn the stump out. Still others use an archeological approach, leaving the stump as an artifact.

New equipment and services are available. For a price, someone will come to your house and grind the stump into wood chips and sawdust.

If you want to save money and effort, you can use an accelerated natural method for removing stumps. This method uses natural decay fungi in the soil, moisture and some added fertilizer to decay stumps. Over several years, even the biggest stump can be dissolved away.

First, cut the stump as low to the ground as you can. When you remove a tree, you can pull soil away from the stump base to make a low cut. The lower the stump, the better.

Next, scar the top of the stump to make slits, lines, and holes. This increases the surface area of the stump top. Then water the area around the stump. Water 5-10 feet beyond the stump as well as the surface of the stump itself.

Try to keep the soil and stump moist, but not wet. Water-saturated soils and wet stumps don't support rapid wood decay. The decay of a stump requires both moisture and oxygen, so don't limit or block oxygen movement into the soil or stump. In short, don't overwater. Remember: moist, not wet.

Now you can apply a general fertilizer to the stump top and surrounding soil. The ideal fertilizer would contain nitrogen and phosphorus.

The nitrogen should be in both slow-release and fast-release forms. It's helpful, too, if it's in both nitrate and ammonium forms for release into the soil. But you don't have to do extensive shopping for the perfect fertilizer. Just use one with nitrogen in it.

Adding nitrogen to the soil and stump top will help the fungi grow and speed the decay of the stump. From time to time, add a little more fertilizer to move the decay process along.

Thinly covering the stump top with soil and organic mulch will help keep it moist and shade it from sunlight and drying winds. Don't use plastic to cover stumps, because it blocks oxygen.

In some abused and sterile soils, you may need to add more composted organic matter and a scattering of natural forest soils to infect the site with wood decay organisms. The more things "eating" the stump, the quicker it will be gone.

Don't overfertilize or allow fertilizer to wash away. One-half to three-fourths pounds of active nitrogen per 100 square feet of soil area, provided in two to three applications, will move the decay processes along. A single big pile of fertilizer on the stump top will actually hinder decay.

After all that, just be patient. Nature will dissolve the stump away if you provide the right environment.

Kim Coder is a forester with the University of Georgia Warnell School of Forestry and Natural Resources.