In private woodlands, public parks and forests, or virtually any wooded area in this country, we face a problem: weed trees – often non-native or exotic species – that invade and often dominate desirable native species. Weed trees like these are an ecological threat and need to be removed.

I have used the following technique for over a decade and it has worked really well. I use herbicides in this technique. At first, I was reluctant to use an herbicide but have found that it’s the only way to go if you have a substantial number of trees to remove.

Tools

• loppers or hand saw
• herbicide applicator – hand held
• machete or hatchet

The technique I describe here – I call it the “tall stump treatment method,” I have mostly used on buckthorn in a northern climate (Minnesota). However, I believe the technique should work on many other invasive trees. The technique works best for trees of about 1 inch or greater in diameter. These larger trees are the first ones you should get rid of because they will bear fruit and shade out native competition.

Timing – When to begin I find it best to treat trees with chemical in late fall or, better yet, winter. It is easier to see and maneuver without all the foliage. More importantly, it is more effective. If you treat a tree in the spring when the sap is flowing, the chemical will be transported to the leaves. The leaves may die, but the tree survives. In late fall and winter, nutrients are being transported down to the roots. This is where you want the chemical transported too for effective die off.

Stage 1 – Cutting the Tops This first stage can be done at any time of year because it doesn’t involve treatment with chemical. For this first stage, all you need is a pair of loppers or a saw (depending on the size of the trees). I dive into the thicket (wear safety glasses because branches can poke your eyes) and cut each tree about waist height. If there are other branches below the main cut, I cut those off too. This leaves a barren trunk about 2 to 3 feet high. I repeat this cutting technique with all the trees in the area that I plan to treat in this batch.

Next, I haul out all of the cut tops of the trees to a burn pile, chipping area, or other storage area. With tree tops that have berries or seeds, move them carefully to minimize the number of berries that fall to the ground.

This leaves an area of tall stumps. You can leave the tall stumps for several months before applying herbicide. The longer you wait, the more re-growth you will have. However, most of the growth will occur just below the cut (as opposed to at the base of the tree), so it shouldn’t be too problematic.

Stage 2 – Treating the tall stumps For this stage I bring an herbicide spray applicator and a machete or hatchet for notching the bark of the tree. The spray applicator can be relatively compact – similar to the spray bottles used for spray cleaners. For an herbicide, I use glyphosate (common trade name: RoundUp). Try to buy it in high concentration – preferably 40%. You don’t need much herbicide with the technique described here. Make sure you follow the label for the herbicide.

Since the cut tree tops have been removed from the area, I can move around the trees relatively easily. I cut notches (or frills) around the base of the stump and squirt chemical into the notches after making the cut. DON’T WAIT MORE THAN A FEW MINUTES if possible to apply the herbicide after making the cut. Otherwise, the tree’s defense mechanisms will seal off the wound and prevent absorption of the herbicide.

Cut the notches or frills as near to the base of the tree as possible. This ensures that more herbicide will be transported into the roots. Many of the demonstrations on the world wide web of the “frill method” (aka “hack and squirt”) show the frill or line of cuts up the trunk some distance from the base. When I have done this, I find the tree has a greater chance of re-sprouting below the frill, presumably because not all the herbicide was transported to the roots.

When making cuts at the base of the tree, however, be careful not to get dirt into the notches or on your tools. Soil and dust neutralize glyphosate. (In general be very careful if you are applying glyphosate. Do not to get dirt on the cutting tools or applicator nozzle.)

If possible, leave the strips of bark from the notches attached to the tree. These attached strips have exposed inner bark that absorb chemical exceptionally well. With this application of herbicide the tree should die within a couple weeks even in the winter.

Stage 3 – Cutting the stumps to the ground For appearance’s sake, you may wish to go back to the area a few weeks later to cut the stumps to the ground level. Since the tree should have died, you can cut them at any level. If you do make a cut to the stump and notice living tree tissue, you can re-apply herbicide at this time. Alternatively, you can simply leave the tall stumps standing and then break them off after they rot.

Advantages of the Tall Stump Treatment Technique Although I like to avoid using herbicides (i.e., pesticides) to eradicate exotic species of trees, I believe you have to if you have a job of any size. I also far prefer the tall stump application method outlined here to foliar, basal bark, or soil treatment methods. I don’t really consider those to be options because of concerns about environmental effects, the quantity of herbicide needed, and efficacy.

There are also number of advantages to the tall stump technique over the traditional cut-stump application, frill, or drilling methods:

1. By breaking the task up in stages, you have fewer tools to carry and keep track of. This means you can work faster and not lose track of tools.
2. You can remove the tree tops from the treatment area without hurrying (unlike with the traditional cut-stump method where the stump faces have to be treated immediately after cutting).
3. You can wait a long time – up to several months – between the initial cutting creating the tall stumps and the herbicide treatment.
4. If there’s snow on the ground, it’s easier to find the tall stumps for treatment.
5. The amount of exposed cambium is greater with this method than with the traditional cut stump treatment method. More pesticide can be held on the strips of bark and in the notch and you can more effectively destroy the weed tree.
6. If you forget to treat one of the tall stumps or if a treatment fails for some reason, the branches will re-grow just below the cut but well above ground level. You can generally make another, single cut just below this re-growth. On the other hand, if you leave an untreated stump cut at ground level, the stump will re-sprout forming a bush, and you will have to cut all the branches and treat each one.
7. With the cut stump method, if you treat the stump face, it’s hard to know which stumps have been treated unless you use a dye. However, some dyes reduce the efficacy of glyphosate.
8. I find it easier to walk in an area with the higher stumps. I trip too easily on short stumps, especially if there’s snow on the ground or high grass.

That’s my treatment technique. If you have looked around the web, you know that nearly everyone who has worked a lot in removing invasive or exotic trees has different techniques. Learn something from the all.