Improper pruning can cause a healthy but overgrown tree to quickly suffer and decline. Although it's important to know how to properly prune a tree, it's also important to know what practices to avoid.

1. Stubbing

Stubbing is when a stub is left on the trunk after you cut off a branch. Trees can't heal over these stubs easily, so they tend to rot on the tree — which invites all sorts of pests to feed on the stub and eventually invade the tree. All branches, no matter their size, need to be cut flush to the raised bit of wood, called a branch collar, that seals the branch to the trunk.

2. Cut Sealing

It used to be a normal procedure to paint over the cut after removing a large branch. It was thought that this protected the tree from insect damage. It actually can slow down the natural healing of the wound that a tree performs on its own, which in turn makes it more likely for the cut to become infected.

3. Topping

Topping is when a tree is cut flush across the top, resulting in an odd flat-topped shape. This may handle the immediate problem of a too-tall tree, but in the long run, the tree will suffer. A topped tree is more likely to split since the weight from snow can settle on the top. Fewer leaves in the topped portion may also affect energy production in the tree. If height must be controlled, it's better to selectively prune branches to maintain the proper shape of the tree.

4. Over-pruning

It can be all too easy to get carried away when you are pruning and remove too many branches. Over thinning weakens a tree so that it may become more prone to disease or death. As a basic guideline, one should never remove more than a third of a tree's branches. Generally, only those that are dead, diseased, or rubbing together need to be pruned out, but additional thinning may be necessary depending on the specific tree.

5. Disease Spread

Poor pruning hygiene practices can spread disease or insects between your trees. Fungal spores, bacteria, or insect eggs can hitch a ride on your pruning saw when you trim an affected tree. Then, when you cut into a healthy tree, you spread these issues to a new tree. Tools need to be cleaned and disinfected between uses to prevent this from occurring.

Avoid these mistakes by contacting a tree trimming service in your area for all of your pruning needs.