8 Ways to Safely and Effectively Kill a Tree

Options for Tree Removal

digging up tree stump
Carol Heffernan

Most of the time, homeowners welcome trees on their property. But some trees are invasive species that, over time, can take over a garden. Other trees may overwhelm your home, digging roots into the foundation or limiting access to light.

Whatever the reason, if you're ready to kill a tree, you'll need to review your options and make an informed choice about the best method for your particular situation.

If you are concerned about chemicals or are removing a tree in an area where you grow fruits or vegetables, you may choose to physically remove the tree. If you are comfortable using chemical herbicide, however, you have a number of options available to you.

Physical Tree Removal

Chemical herbicides are effective and relatively low cost. On the other hand, they involve using potentially harmful substances in your own backyard. There are ways to mitigate the risk involved, but you may prefer to avoid chemicals altogether. In that case, you have two options for tree removal: cutting down or starving the tree.

Cutting Down a Tree

If you are removing a very large tree or are uncomfortable with using a chainsaw, you may want to hire someone to take down your tree. Many people, however, simply cut down their own trees. Once the tree has been cut to a stump, you'll need to grind the stump to the ground.

Unfortunately, cutting and grinding may not be enough to kill your tree. In some cases, trees will continue to sprout from the trunk. When this happens, you will need to systematically look for the new sprouts and cut them down religiously whenever they appear. By cutting the sprouts, you deny the roots the energy they need to continue to grow.

If neither grinding the stump nor cutting sprouts is enough to kill your tree, you'll have to dig down and painstakingly remove the roots from the soil. The notorious buckthorn bush/tree is an example of a species that can only be killed by completely removing the roots.

Starving a Tree

The bark of a tree is a system for transporting soil nutrients and moisture to the branches and leaves. With some trees, fully removing the bark around the circumference of the tree's trunk will effectively starve it to death. This technique is called "girdling." Girdling is often effective, but it is not foolproof. In some cases, trees can bypass or "jump" the girdle.

To get the best results, it's important to remove all the layers of bark in a circle around the tree, cutting about 1.5 inches deep with a hatchet or ax. The girdle will need to be about two inches wide to kill a small tree, and up to eight inches wide for a large tree. 

Chemically Killing a Tree

Herbicides can kill trees, and, properly applied, they can be safe for the environment. The most environmentally-friendly options involve applying herbicide to a specific area of the tree. In some cases, however, the only viable option is to use herbicidal spray.

There are five major types of herbicides, only some of which are rated for home or crop use. Triclopyr amine and triclopyr ester are both growth regulator-type herbicides, while glyphosate and imazapyr kill plants by interfering with the synthesis of plant proteins. Aminopyralid is primarily effective on legumes such as kudzu, but may not be appropriate for your particular needs.

Cut Surface Treatments

This technique involves creating a pathway through the bark so that herbicide can be introduced into the plant's vascular tissue. Start by making a series of downward cuts around the circumference of the tree with an ax or hatchet, leaving the frill (cut section of bark) connected to the tree. Immediately apply the selected herbicide into the cuts. Avoid spring applications when sap flowing out of the wound will prevent good absorption.

Injection Treatments

Use specialized tree injection equipment to administer a specific amount of herbicide into the tree when the cut is made. Treatments are effective when injections are made every 2 to 6 inches around the tree. For best results, treat trees 1.5 inches or more diameter at chest height. Injection is often handled by a tree removal company because it does require an investment in equipment.

Stump Treatments

After cutting a tree down, you can minimize the possibility of regrowth by immediately treating the freshly cut surface with herbicide to prevent sprouting. On larger trees, treat only the outer two to three inches, including the cambium layer, of the stump (the internal heartwood of the tree is already dead). For trees three inches or less in diameter, treat the entire cut surface. 

Basal Bark Treatments

Apply herbicide to the lower 12 to 18 inches of the tree trunk (on the bark) from early spring to mid-fall. Some species can be treated during winter. Use herbicide spray mixed with oil until the bark is saturated. The low volatile ester formulations are the only oil soluble products registered for this use. This method is effective on trees of all sizes.

Foliage Treatments

Foliar spraying is a common method of applying herbicides to brush up to 15 feet tall. Make applications from early summer to late September, depending on the choice of herbicide. Treatments are least effective during very hot weather and when trees are under severe water stress.

Soil Treatments

Certain soil treatments applied evenly to the soil surface can move into the root zone of the targeted plants after ample rainfall or overhead moisture. Banding (also called lacing or streaking) applies concentrated solution to the soil in a line or band spaced every two to four feet. You can use this type of application to kill large numbers of trees.

Important Tips to Remember

Before starting a tree removal project, learn how to use herbicides safely and legally. Herbicides treatments of roots or soil (or sprayed herbicides) can kill vegetation unintentionally.

  1. Call your local Cooperative Extension Service for detailed chemical information pertaining to any chemical treatments used. You are responsible for the chemicals you use and their ultimate effects.
  2. When using frilling or cut stump methods of treatment, apply the herbicide immediately so that your tree doesn't have a chance to start healing itself and you can achieve maximum absorption.
  3. Roots of plants can share vascular tissue through root grafting. Root grafting occurs primarily within the same species but may occur between plants within the same genus. Your herbicide can move from a treated tree to an untreated tree, killing or injuring it.
  4. Once the herbicide is released from a tree, it can be available for uptake by another. The serious consequence of this is that a treated tree may release herbicide back into the environment, injuring other nearby trees and vegetation.
  5. Adding stains or dyes to the herbicide solution substantially increases applicator accuracy. Applicators use the dyes to monitor treated trees, so they are less likely to miss or respray targeted trees. Use of stains can also indicate personal exposure.
  1. Be careful to avoid applying herbicide in areas where it can injure other plants. Assume that tree roots extend a distance equal to the height of a tree in dry climates, and equal to half of the height of a tree growing in a wetter environment.

 

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Nix, Steve. "8 Ways to Safely and Effectively Kill a Tree." ThoughtCo, Feb. 18, 2018, thoughtco.com/kill-a-tree-using-herbicides-1343355. Nix, Steve. (2018, February 18). 8 Ways to Safely and Effectively Kill a Tree. Retrieved from https://www.thoughtco.com/kill-a-tree-using-herbicides-1343355 Nix, Steve. "8 Ways to Safely and Effectively Kill a Tree." ThoughtCo. https://www.thoughtco.com/kill-a-tree-using-herbicides-1343355 (accessed May 26, 2018).