By Joe Zeleznik, Forester

NDSU Extension

I used to be a big college basketball fan. Every year I would follow the Top 25 teams and try to figure out who would make it to the tournament and which teams would be matched up in the bracket.

As I get older, the term March Madness has changed meaning for me. It’s more about getting out of the house and into the sunlight and enjoying the longer days and hopefully, warmer temperatures.

My March Madness comes around when I get the urge to prune trees. And I know I’m not alone with that impulse. There’s a lot to be said for taking off branches and turning a tree with poor structure into something that will have a solid scaffold for the long term.

And quite simply, it’s good exercise, especially after sitting around all winter and working on jigsaw puzzles.

People sometimes wonder how pruning can be good for a tree. We’re creating wounds and removing branches and, therefore, the leaves. Those leaves are the tree’s “food factory,” producing sugar during photosynthesis.

Fewer leaves, less sugar, less growth. Right?

As it turns out, deciduous trees can lose up to about 25% of their leaves without even feeling any stress. I rarely get close to that 25% limit when I’m pruning, so I’m not too worried about it.

The question of which branches to remove is sometimes a bit more challenging. Why would we want to remove branches?

Anyone who’s ever gotten whacked in the face while mowing the lawn can answer that question. Clearance pruning is a common reason. Whether it’s clearance for the lawn mower, removing branches that hit the house, or branches over the street and sidewalk, getting rid of those lowest branches is probably the most common reason for pruning.

Removing injured, diseased or dead/dying branches is also high on the list of reasons why we prune trees. Dead branches can be removed at any time of the year.

Deciding which branches to remove can be pretty challenging. Well, clearance pruning is straightforward. But structural pruning can be a bit more tricky. We sometimes prune trees in order to build “good structure”.

What makes for good structure? A scaffold of healthy, well-spaced branches that are evenly distributed around the tree. The scaffold is made up of those branches that will become large, supporting a vast number of smaller branches and leaves. And together, those branches and leaves make up a dense, healthy crown.

Ideally. Unfortunately, trees are rarely ideal and they don’t follow the diagrams that we see in the books. That’s why I tell people to take what nature gives you and make the best of it.

And don’t worry about it. There’s more than one right way to prune a tree and trees are pretty forgiving. Do the best you can and then step away and let the tree do its thing.

I will add one caution, though. Please don’t top your trees. These techniques can cause big problems for trees as they potentially remove large amounts of leaves while creating large wounds that are slow to grow over. Topped trees are also more prone to insect and disease damage.

There are many great sources of information about pruning trees, including your county NDSU Extension office. We have an informative video available at https://bit.ly/NDSUprune.

The most important thing right now is to just get out and do it. March is a great time to prune trees. Enjoy!

NDSU Agriculture Communication – March 6, 2024

Source: Joe Zeleznik, 701-231-8143, joseph.zeleznik@ndsu.edu

Editor: Kelli Anderson,701-231-6136, kelli.c.anderson@ndsu.edu