Strategic pruning can boost crop production in fruit trees

It takes a lot of energy from the rooted plant to produce fruit, so properly maintaining and training a fruit tree will produce a quality harvest.

Pruning fruit trees is an art that requires practice and experience. Sometimes people prune to keep busy, but it should be a well-planned, thoroughly thought-out activity in the garden.

First, set a goal for your fruit tree to guide your pruning practices throughout the tree’s life span, and continually revisit these goals. Goals might include producing large fruit or a large quantity of fruit, keeping the tree height low, keeping the branches at a harvestable, or reachable, height or maintaining an open canopy. Don’t wait to prune until the tree is large. Pruning should be seen as a regular maintenance activity.

To encourage fruit production, home gardeners and school gardens should concentrate on pruning and pollination. Pollination is a huge contributor to fruit tree production. Pruning is a tool that can reduce stress on the tree to produce quality fruit. All successful farmers in the fruit tree business practice proper pruning and are good hosts to pollinators.

Fruit trees produce fruit to reproduce. Inside each botanical fruit is a seed or seeds that will guarantee its survival. In general, trees produce more fruit than they can support nutritionally. Thinning branches on a fruit tree naturally decreases fruit production. However, the fruit that are produced on remaining branches are treated to optimal nutrition and sunlight to develop to their potential. Excessive fruit results in a large quantity of small fruit because they are all fighting for nutrition and carbohydrates.

Keeping the tree height low is attainable by reducing vertical branches and encouraging more horizontal growth. This is where pruning fruit trees at a young age is beneficial. If you start early, you can prune branches that grow straight up to the sky and leave those that extend perpendicular from the trunk of the tree.

Mature trees can also benefit from this type of pruning; however, keep in mind that the general rule of thumb to maintain tree health while pruning is to never prune more than a third of the canopy at a time. Maintaining horizontal growth will result in harvestable branches — so no need for bamboo stick and ladder.

An open canopy is achieved by taking a step back and really looking over the tree. If you see lots of small branches, this is an opportunity to open up the canopy. Just a few large branches are needed for production.

I have seen mature mango trees maintained at 6 feet tall with very few branches. Each branch was selected over a period of time to be the best to bear the weight of each prized mango. Thinning the fruit is also practiced to produce a few valuable mangoes instead of the many mangoes that may be produced in a growing season. Each fruit is then bagged to prevent pest damage and presented at market for premium price.

The Aloha Arborists Association, an organization of tree-care professionals, is hosting a workshop on Oahu to share the expertise of its members. Join us from 9 a.m. to noon Saturday at the University of Hawaii Urban Garden Center in Pearl City to learn about optimizing fruit production using pruning techniques and about the importance of pollinators.

Bring in a picture of your fruit tree to discuss pruning tips with UH Master Gardeners. Call 453-6050 to register, or visit us at www.ctahr.hawaii.edu/ougc for more details.

Jayme Grzebik is an urban horticulturist for the University of Hawaii’s College of Tropical Agriculture and Human Resources Cooperative Extension Service and statewide coordinator of the UH Master Gardener Program. She can be reached at grzebik@hawaii.edu, or visit www.ctahr.hawaii.edu/UHMG.