Which method involves creating frills in the bark for treatment?

The method that involves creating frills in the bark for treatment is hacking. This technique is often used in vegetation management and control, particularly for treating unwanted trees or invasive species. Hacking creates small cuts or frills in the bark, which allows for better penetration of herbicides into the tree’s vascular system. This can effectively disrupt the tree’s way of moving nutrients and water, leading to its eventual decline and death when used appropriately with the right chemical treatments.

The other methods listed serve different purposes: girdling involves removing a strip of bark around the trunk of a tree, effectively cutting off nutrient transport, while grafting is a horticultural method for joining two plants to grow as one. Pruning, on the other hand, refers to trimming plants to maintain their shape or health. Each of these methods has its own specific applications in plant management, but hacking is distinct in its application of frills specifically in the bark for treatment purposes.