Does Cutting Down a Fir Tree Kill the Roots?

Recommended Chemicals

• A number of herbicides may be applied to the stump of a fir tree to kill the roots. These include products containing 2, 4-D+triclopyr, ammonium sulphanate or sulfur cholorate, suggests the Reader's Digest Association in "1001 Hints & Tips for Your Garden." Check with local state environmental officials to see if the use of the selected herbicide is allowed in the area, as rules may differ by state.

Treatment Method

• One way to kill the fir stump and roots is to drill the herbicide into the stump. Use a regular drilling machine to create several holes on the stump surface. Pour in the selected herbicide into the holes. The chemical is translocated down to the tree roots and will kill the roots and, consequently, gradually kill the entire stump.

Brushing Method

• It is also possible to apply the herbicide to the stump by brushing onto the fir tree stump. This needs to be done as soon as possible after cutting the stump while tree tissue is fresh. Make the surface level to keep the chemical from running off. If the fir tree stump diameter is three inches or less, brush herbicide on the entire surface area. On larger trees with trunk diameter of more than 3 inches, brush only the 2 to 3 inches right next to the bark. The chemical moves to the roots and kills the entire stump along with the roots.

Use Recommendations

• When selecting herbicide for brushing on the fir tree stump, choose the water soluble amine formulation of triclopyr and 2, 4-D rather than the esters as the former provide better efficacy, recommends the Washington State University Extension. The best time for treating stumps is during summer and early fall. If the application of herbicide to the fir tree stump is delayed for any reason, re-cut the surface again to expose fresh tissue prior to application of the chemical.