Herbicide Injections, Directed, & Spot Sprays For Pine Release Hardwoods

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This is the time of the year when we think about burning and herbicides use when we are trying to clean up hardwoods in pines. When we are preparing to burn and not enough fuel on the ground, we may need to treat individual trees. This past week, I’ve had discussions about wide-spaced injection techniques and basal bark techniques.

Wide-spaced Injection

When we have larger diameter trees, greater than 6″ diameter, we use this technique called hack and squirt. All you need is a small hatched and spray bottle. Imazapyr and triclopyr are commonly used for herbicides which are mixed with water. Depending on concentration of herbicide in solution is how many cuts we make in the tree. If 25% Arsenal AC or 50% Chopper is used, make 1 cut into the stem for each 3″ of tree diameter. (A 3″ diameter stem will receive 1 cut while a 6″ diameter stem will receive 2 cuts.) The cut goes right into the outer bark of the tree. You spray the solution into each cut.

Basal Bark

For hardwoods that are 6″ or less in diameter, we can use a herbicide mix with oil and spray the lower bark. This is called basal bark, thinline, or streamline treatment. We want a 20-30% of triclopyr and a 70-80% oil. You can mix this in a sprayer on a backpack or gallon sprayer. One of the questions we get is type of oil. Deisel fuel is commonly used as the oil, but the smell is not fun to deal with. Here is some information on oils and treatment specifications from UGA Extension Forester Dr. David Moorhead:


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