Topping is defined as “the drastic removal of large branches with little regard for location of the pruning cuts”. Topping provides the illusion of quickly reducing the size or height of the tree. It is not a practice that should be performed by any certified arborist. Instead, there are professional pruning techniques to limit the height of a tree and keep it healthy.
Other names for topping include ‘heading,’ ‘tipping,’ ‘hat-racking,’ and ’rounding over.’
Problems Caused by Topping
- Starvation. Good pruning practices rarely remove more than 1/3 of the crown, which does not seriously interfere with the ability of a tree’s leafy crown to manufacture food. Topping removes so much of the crown that it upsets an older tree’s well-developed crown to root ratio and temporarily cuts off its food-making ability. The tree goes into shock and readily produces new shoots.
- Weak new growth. The branches that sprout following topping are much more weakly attached than a naturally developed branch. Rot at the severed end of the limb can make a bad situation even worse.
- Rapid new growth. The goal of topping is usually to control the height and spread of a tree. However, it usually has exactly the opposite effect! After topping, trees vigorously re-sprout. The resulting sprouts are far more numerous than the normal new growth and they elongate so rapidly that the tree returns to its original height in a very short time.
- Insects and disease. The large stubs of a topped tree have a difficult time sealing. Thus the stubs are highly vulnerable to insect invasion and decay.
Six Good Reasons NOT to “Top”
- Tree Death: Trees, some more than others do not tolerate topping, the excessive removal of foliage may cause the tree to die within one growing season by limiting the tree’s ability to produce food.
- Rapid New Growth: The most common misconception with topping is that ‘it keeps trees small’, on the contrary topping promotes the rapid growth of new vigorous branches known as water sprouts. Water sprouts grow 4 to 10 times faster than normal limbs creating taller, structurally inferior branches than the original limbs.
- Increased liability / Hazards: New sprouts develop at the edges of the cut branches. They are weakly attached and prone to failure with there increased growth rate. As the original stub cut rots, the sprouts will fail even sooner, increasing risk and liability.
- Ugliness: Topped trees are unnatural and unappealing; the apical dominance genetically programmed within the tree will never return to its original grace.
- Pests and Disease: Topped branches have large wounds that cannot seal nor defend the wound from insects and decay. Rot extends into the stem causing the stem to rot, increasing pest and disease which results in tree death or removal.
- Cost: At first topping may appear to be the cheaper solution to reduce the size of your tree, trees that die from topping will need replaced, ugly trees reduce property values, dead stubs become liabilities, overall maintenance cost increase with time. Topping is more expensive in the end.
For information on appropriate tree pruning practices click here