What type of herbicide application is effective on large trees using cuts around the base?

A frill treatment is a specific method of herbicide application designed for large trees. In this technique, shallow cuts or frills are made into the bark around the base of the tree, which allows the herbicide to penetrate the vascular system more effectively. This method targets the tree directly and minimizes the risk of harm to surrounding vegetation. The application is typically done in a way that ensures the herbicide is absorbed into the tree, leading to a successful kill of the unwanted tree.

The other application methods, while relevant in certain situations, do not specifically utilize cuts around the base of the tree in the same manner as the frill treatment. Stump treatments target the freshly cut surface of a stump to prevent regrowth, while cut surface treatments involve applying herbicide to fresh cuts on the tree but may not be based entirely around the base like the frill method. Therefore, the frill treatment is the most effective and targeted approach for applying herbicide to large trees using cuts around the base.