Tree topping is an indiscriminate pruning practice that involves cutting large branches back to stubs, leaving a mutilated, unnatural appearance. This destructive process, also known as “hat-racking” or “heading,” is performed to quickly reduce the size or height of a tree without regard for its health or structure. Topping creates significant biological damage, severely stressing the tree and making it more hazardous. Restoration pruning is a multi-year process that attempts to repair this harm and re-establish a stable crown structure.
The Biological Harm Caused by Topping
The large, stub-like wounds created by topping cuts are too extensive for a tree to seal off effectively. Unlike proper pruning cuts made at the branch collar, these cuts leave long stubs that the tree cannot readily compartmentalize. This lack of compartmentalization allows open wounds to serve as direct entry points for decay fungi and bacteria. Rot moves swiftly into the heartwood, compromising the tree’s structural integrity.
Topping removes a significant portion of the leaf-bearing crown, which is the tree’s food-producing factory, leading to starvation. The tree responds to this severe stress by activating latent buds near the cut, forcing the rapid growth of numerous, vertical shoots known as epicormic sprouts or water sprouts. These new shoots grow quickly but are weakly attached to the parent branch, lacking the strong wood tissue connection of a naturally formed branch. This weak attachment makes the fast-growing regrowth prone to breaking in wind or storms, creating a greater long-term safety hazard.
Determining if Restoration is Possible
The first step in restoration is a careful assessment to determine if the tree is a candidate for repair or if immediate removal is the only safe option. A primary consideration is the tree species; some, like oak, maple, and beech, recover poorly from the stress of topping and may be better removed. Younger trees possess greater vigor and stored energy reserves, allowing them to handle the stress and respond to corrective pruning better than mature trees.
The extent of existing decay is another determining factor, requiring a thorough inspection of the main trunk below the topping cuts. If decay has progressed deeply into the trunk or the tree has been repeatedly topped, the structural compromise may be too severe to safely support the new growth. Restoration is a long-term commitment, requiring several years of dedicated work. It is not worthwhile if the tree is already a significant failure risk. Consulting with a certified arborist is necessary to accurately evaluate the risk and determine the tree’s realistic chance of survival and stability.
Steps for Crown Restoration Pruning
The goal of restoration pruning is to gradually thin the dense flush of epicormic sprouts to select new, permanent branches that will re-establish a natural crown structure. The process begins in the late winter or early spring, at least one full growing season after the initial topping incident. This delay allows the tree to produce the necessary sprout growth needed for selection.
In the first year of restoration, select the strongest, best-positioned sprouts on each stub, aiming to keep only two or three per topping cut. The chosen sprouts should be growing with an upward, vertical orientation and be free of damage. All other competing sprouts should be removed to concentrate the tree’s energy into the selected leaders. The chosen sprouts must then be reduced by approximately half their length using a proper heading cut back to a lateral bud or smaller branch. This initial reduction slows the growth of the selected shoots and helps establish a hierarchy.
The second and third years involve follow-up pruning to further refine the crown structure. On each stub, select the single best-growing sprout to become the permanent branch, known as the new leader. The temporary sprouts reduced in the first year should be either removed entirely or heavily reduced again with reduction cuts back to a strong lateral branch. This multi-year process continues until a single, well-spaced, strong branch is developing from each original stub, guiding the tree toward a more natural form.
Ongoing Care and Future Proper Pruning
Following restoration pruning, ongoing maintenance is necessary to support the tree’s recovery from severe stress. Adequate watering is beneficial, as the tree has lost a large portion of its canopy and may struggle to regulate moisture. Light fertilization may be appropriate if a nutrient deficiency is observed, but this should be done cautiously to avoid stimulating excessive, weak growth.
Once the crown structure is restored, future pruning should utilize proper arboricultural techniques to manage tree size and health without repeating the damage.
Crown Reduction
This technique involves selectively shortening branches back to a lateral branch large enough to assume the terminal role, which maintains the tree’s natural shape.
Canopy Thinning
This removes inner branches to improve light penetration and air circulation without removing the top of the tree. These methods ensure that size management is achieved through cuts a tree is biologically equipped to close, preventing the decay and structural hazards associated with topping.