Last week we talked about things to consider when you are planting trees or planning urban landscapes. You put a lot of time and money into the types of trees you planted and where you planted them. This week we want to discuss how to take care of them now that they are growing.

We take care to feed our children properly to help them grow. We nurture them and discipline them at times to train them to do things the right way.  Trees planted in the urban forest also need nurturing, and at times, “discipline” pruning to grow the right way to become structurally sound in form. I do not recommend pruning trees for about 2 years after planting, since they are still taking root and need all their foliage to provide food for the expansion of the roots. Removing dead limbs is fine but making proper pruning cuts is important. As your tree becomes a juvenile, ensuring proper form is very important and this a great time to prune because the has ample amounts of energy energy to recover from pruning cuts. Training for a structurally sound tree includes pruning for a single central trunk with evenly spaced scaffold branches. Removing crossing and rubbing limbs and branches growing back toward the center of the tree is also important. Once a tree reaches a height where you need to leave the ground to prune, it is best to contact your local certified arborist.  The most common mistakes I see when homeowners prune their tree are flush cuts. Flush cuts are when you remove the branch collar of the limb. An easy analogy to visualize is if you hold up your hand and find you thumb knuckle. A flush cut would be like removing your thumb and knuckle while cutting right to your hand. Proper pruning would be making the cut right outside of the “knuckle.”  Flush cutting removes the branch bark collar which holds important cells that allow for compartmentalization of decay in the tree. A common misconception is that trees “heal.” In reality, they only compartmentalize their wounds, walling off decay. Mature tree pruning really is more for aesthetics and safety. Removing deadwood from mature trees that can fall a distance will help keep homeowner and their property safe. Another reason to remove limbs or deadwood from mature trees is to ensure that proper cuts can be made so the tree can compartmentalize the wound and keep out decay fungi from growing in the dead wood.