Topping damages hundreds of trees each year. Many people are unaware of the detrimental effects of topping. Trees are subjected to a number of stresses during their lifetime. Topping also is a form of stress but it is a stress that can be avoided.
Topping involves drastic removal or cutting back of large branches in mature trees leaving stubs. Topping can make a tree hazardous and reduce its life. This practice frequently is the result of trying to manage trees incorrectly planted under power lines or too close to structures. Site selection must be considered before planting in order to provide the tree with sufficient room to grow.
Some homeowners believe stimulation of new growth associated with topping actually is beneficial to the tree. Although the tree appears rejuvenated with new foliage and branches, this only serves to mask the real damage.
Trees mistakenly are topped, under the best of intentions, to remove potentially hazardous dead and diseased branches. Unfortunately, topping indiscriminately removes healthy and unhealthy limbs. Problem limbs are best removed by selective pruning.
In some situations, removing large limbs may be necessary. However, correct pruning alternatives such as proper early training, selective thinning out of branches and limbs or whole tree removal should be considered and adopted.
Removing much of the tree canopy upsets the crown-to-root ratio and cause serious interruption of the tree’s food supply and exposes bark to the sun. A 20-year-old tree has developed 20 years’ worth of leaf surface area. This leaf surface is needed to manufacture sufficient food to feed and support 20 years’ worth of branches, trunks and roots.
Removing the tree’s normal canopy suddenly exposes bark to the sun’s direct rays, often scalding newly exposed outer bark. Serve sun scald will cause the bark to split and obstruct the flow of nutrients.
Topping not only cuts off a major portion of the tree’s food-making potential, it also severely depletes the tree’s stored reserves. It is an open invitation for the tree’s slow starvation.
Large branch stubs left from topping seldom close or callus. Nutrients are no longer transported to large stubs and that part of the tree becomes unable to seal off the injury. This leaves stubs vulnerable to insect invasion and fungal decay. Once decay has begun in a branch stub, it may spread into the main trunk, killing the tree.
Topping removes all existing buds that ordinarily would produce normal sturdy branches and instead stimulates regrowth of dense, upright branches just below the pruning cut. The water sprouts or suckers that result from topping are not well integrated into the wood of the tree and because of their weak connections and vulnerability frequently break. Large limbs then fall creating a dangerous situation that must be remedied by tree removal.
Since water sprout regrowth generally is rapid and vigorous, a topped tree often will grow back to its original height faster and denser than a tree that has been properly pruned or thinned. This makes topping, at best, only a temporary solution for oversized trees.
Some tree species such as sugar maple, oak and beech do not readily produce water sprouts. Without the resulting foliage, a bare trunk results and the tree quickly dies. Deteriorating branch stubs, along with weak sucker growth, make topped trees vulnerable to wind and ice damage.
From an aesthetic aspect, topping disfigures the tree. Unsightly branch stubs, conspicuous pruning cuts and a broom-like branch growth replace its natural beauty and form.
Unfortunately, even some “knowledgeable” tree services indiscriminately top trees. Avoid patronizing companies that advocate topping.
Here is a list of trees for small spaces, under 25 feet tall: trident maple, flame maple, box elder maple, small japanese maple cultivars, tatarian maple, autumn brilliance serviceberry, fringe tree, kousa dogwood, winter king hawthorn, leprechaun ash, amur maackia, various cultivars of flowering crabapple, leonard messel magnolia, star magnolia, snow fountains cherry, snow goose cherry, weeping yoshino cherry, ivory silk tree lilac and various weeping tree varieties.