The practice of cutting the top off a cedar tree, commonly called “topping,” is the indiscriminate removal of the main vertical leader or major upper branches to reduce height. While this may seem like a quick solution for an oversized tree, arborists universally discourage this action for coniferous trees like cedars. Topping is detrimental to the tree’s long-term health and aesthetics and is considered an unacceptable practice in professional arboriculture. The resulting damage often leads to stress, decay, and structural failure.
Why Topping is Harmful to Cedar Trees
Removing the tree’s entire upper canopy creates large, open wounds that the cedar cannot effectively close or seal. Unlike proper pruning cuts made just outside the branch collar, topping cuts leave stubs that expose the inner sapwood and heartwood. These massive, unhealed wounds serve as direct entry points for fungal pathogens and wood-boring insects, leading to rapid internal decay.
The sudden and severe removal of foliage, often 50 to 100 percent of the crown, temporarily “starves” the tree by limiting its ability to photosynthesize. This stress forces the tree into a survival mechanism, rapidly activating dormant buds below the cuts. The result is a dense eruption of multiple, weak, vertical shoots known as epicormic growth or water sprouts.
These new shoots are structurally weak because they lack the strong overlapping wood tissues of naturally grown branches. They are only superficially attached to the parent branch, making them prone to breaking off in high winds, heavy snow, or ice storms. This ultimately makes the topped tree more hazardous than it was before the cut. The loss of the canopy also exposes previously shaded bark on the trunk and upper limbs to intense sunlight, which can cause severe sunburn and tissue damage.
Understanding the Cedar Tree’s Natural Growth Pattern
Cedars, like most conifers, exhibit strong apical control, giving them their characteristic pyramidal or “excurrent” shape. This growth is regulated by the terminal bud, which produces the hormone auxin that suppresses the lateral growth of lower branches. When the central leader is removed, this hormonal balance is disrupted, triggering the chaotic growth response seen in topped trees.
The biology of a conifer’s wound response differs significantly from many deciduous trees. While some hardwoods can actively compartmentalize and wall off large wounds to prevent decay, cedars have a limited ability to defend against the multiple, severe wounds caused by topping. This difference means decay organisms can move more freely into the tree’s core.
Cedars rely heavily on their terminal buds for vertical trajectory and lack the widespread supply of latent buds found in many broadleaf species. If the top is cut back to old, brown wood that lacks green foliage, the cedar may not be able to generate new growth. This makes the recovery of a topped cedar difficult or impossible, often leaving a permanently disfigured specimen.
Safe Methods for Managing Tree Height
For a tree that has outgrown its space, the correct approach is professional crown reduction pruning, not topping. This technique involves selectively shortening branches by cutting them back to a suitable lateral branch or bud. A proper reduction cut requires the remaining lateral branch to be at least one-third the diameter of the removed limb, ensuring the new growth maintains structural integrity.
Another management strategy is selective thinning, where an arborist removes smaller, interior branches throughout the crown. This process reduces the overall bulk and weight of the tree, which lowers wind resistance and minimizes storm damage while preserving the tree’s natural shape. Removing lower branches, known as crown raising, can lift the canopy away from structures or walkways without significantly affecting height.
For large trees or those near utility lines, consulting a certified arborist is the most important step, as they possess the knowledge and specialized equipment for safe, effective height management. An arborist can assess the tree’s health and apply techniques like directional pruning to guide growth away from obstacles. If a cedar is too large for its location and cannot be managed safely, the final option may be complete removal and replacement with a smaller, appropriately sized tree species.