MARCH
2003

 

 

 

By
B. Rosie Lerner
 
Purdue Extension
Consumer
Horticulturist

 

 

 

 

 

3-20-03

Topping is Hazardous to Your Tree

Tree topping is an all too common practice among homeowners, particularly when their trees become too tall and pose a possible threat to the house or overhead power lines. Some have the trees topped because they believe, or are led to believe, that topping is a good pruning practice. 

Obviously, some situations require the removal of large limbs for the sake of safety. But topping is a drastic step and ultimately endangers the tree's life. Removing such a great quantity of growth in one shot throws off the balance of roots to shoots that the tree has gradually developed all those years. The much-reduced leaf surface will not be able to manufacture sufficient food reserves to feed the large root system. As roots starve, the rest of the tree will suffer from insufficient moisture and nutrients. 

Another drawback to topping for many tree species is the stimulation of numerous, upright branches that grow straight up. These shoots are typically very soft, weak growth that breaks easily and is more susceptible to attack by diseases and insects. These shoots are rapid growers, so the tree will soon be back to its original height. And, the stubs left by the topping are usually too large for the tree's defense process of callusing to heal over. Thus, the stubs also become easy prey for insects, diseases and decay. Even those tree species that do not produce such re-growth will be drastically disfigured by topping.

There are alternatives to topping when size reduction is required. Thinning out the canopy by removing selected branches completely back to their point of origin will reduce the tree's size while maintaining more of its natural shape. The cuts will be less conspicuous and should heal more rapidly. Thinning is a much more time-consuming process and requires a more skilled hand, which usually translates to more expensive. 

If the tree isn't worth the money to do the job right, it's probably better to remove the tree entirely rather than top repeatedly. In the case of overhead power lines, it really is best to remove the tree and replant with a more appropriate sized plant. But if the tree is worth saving, make the investment in a healthy future.

 

Writer: B. Rosie Lerner
Editor: Olivia Maddox