Ringing a tree, also known as girdling, is a precise method used to intentionally cause a tree’s death without immediately felling it. This technique serves as a form of land management or preparation for tree removal by utilizing the plant’s own biology against it. The process involves removing a continuous band of bark and the underlying growth tissue around the entire circumference of the trunk. By severing the internal transport system, girdling prevents the tree from moving essential nutrients between its canopy and its root system. This action begins a slow, controlled decline, which is often preferred when a standing dead tree is desired for wildlife habitat or when a complex root structure needs to decay before removal.
The Biological Mechanism of Tree Girdling
The success of tree girdling relies on disrupting the tree’s vascular system, which is composed of two primary layers. Just beneath the outer bark is the phloem, a layer of tissue responsible for transporting sugars and carbohydrates produced by the leaves downward to the roots for nourishment and storage. Beneath the phloem lies the vascular cambium, a thin layer of cells that produces new phloem toward the outside and new xylem toward the inside.
When the ring of bark and cambium is removed, the phloem pathway is completely severed. This interruption starves the root system, which can no longer receive the necessary energy from the leaves. The inner wood, or xylem, remains intact immediately following a proper girdling, as this tissue transports water and minerals from the roots upward to the canopy. Because the water supply is maintained, the top of the tree may continue to leaf out and appear healthy for a period, but the roots below the cut are slowly dying due to a lack of carbohydrates.
Step-by-Step Guide to Ringing a Tree
Before beginning the girdling process, it is important to gather the appropriate protective gear and tools, including gloves, eye protection, and a sharp cutting instrument. Common tools for this task include an axe, a specialized girdling tool, a machete, or a chainsaw for larger trunks. The location of the ring should be below the lowest branches and at a comfortable height for the operator.
The physical process begins by making two parallel, horizontal cuts that completely encircle the trunk. These cuts must penetrate through the outer bark and the phloem, extending into the vascular cambium layer to ensure the full interruption of nutrient flow. The depth of the cut is crucial; it must reach the sapwood, the lighter, living wood just inside the cambium, but does not need to cut deep into the heartwood.
Once the two parallel cuts are made, the bark and cambium layer between them must be completely removed. A chisel or the blunt edge of an axe can be used to pry and peel away the strip of tissue. The width of this removed band is important for preventing the tree from growing new tissue to bridge the gap; a width of at least four to eight inches is recommended, with wider bands needed for vigorous species or larger trees.
The exposed wood in the girdled ring should be completely clean, showing no traces of the green or white cambium layer, as any remaining strip can allow the transport system to remain partially functional. For an accelerated kill, a suitable herbicide can be immediately applied to the freshly exposed sapwood within the cut. The herbicide is absorbed by the upward-moving xylem and distributed throughout the tree, helping to prevent the rapid regeneration of phloem tissue across the wound.
Monitoring the Outcome and Timeline
After the girdling is complete, the tree’s decline will be a gradual process that can vary significantly based on species and size. Some trees, like oaks, may show signs of decline and die within the first year after the bark is removed. Other species, such as certain maples or birches, possess greater reserves and may continue to produce leaves for up to two or three years before succumbing to root starvation.
The first visible signs of the tree’s decline will typically be a lack of vigor, including smaller or discolored leaves, and a failure to fully bud out in the spring following the girdling. Over time, the canopy will begin to thin, and the top branches will die back as the tree uses its stored energy. The slow death allowed by girdling enables the root system to rot naturally in the ground.
This natural decay of the roots can be a significant advantage, as it makes the eventual removal of the stump much easier and less labor-intensive than immediate felling and grinding. The standing dead tree, known as a snag, will also dry out over time, which reduces the overall weight and makes the wood easier to handle if the tree is to be cut down later. The timeline for full decay and root disintegration can take several years.