|Growth inclusion and the resulting
fungal infection of a five scaffold tree.
I often receive questions regarding pruning first leaf trees. Many growers want to know the strategies of pruning trees. Traditionally, three scaffolds are selected, equally spaced on both the vertical and horizontal plane of the tree. This article discusses this pruning style. Currently, many growers are pruning with more than three scaffolds, and in some cases up to eight or more. Which way is better? In many ways, this decision comes down to economics.
In determining if three scaffold or a multiple scaffold approach, think about how long you want your orchard to live. Pruning to fewer scaffolds will yield an orchard that has the potential to live longer than an orchard with many scaffolds. Why? Selecting scaffolds that are spaced evenly through the tree will reduce formation of canker diseases within the tree as the trees mature (15+ years). Since the scaffolds are spaced more evenly, it will take longer for growth inclusions to form, and the years of growth, and the corresponding rings of xylem, will form a stronger wood, making the tree more resistant to limb breakage. Since fungal infection of the scaffolds is delayed, orchard productivity can be maintained longer. This type of pruning is recommended for growers who don’t mind the longer wait to high productivity, but want the orchard to last a longer time (20+ years)
Pruning to multiple scaffolds (5+ scaffolds) has different benefits.These trees tend to produce larger crops at a younger age. As the tree ages, the branches begin to grow together, growth inclusions form, and trees are lost to fungal infections that weaken and kill scaffolds. There is also an increased risk of wind damage and shaker damage. These trees may have to be tied longer than trees with fewer scaffolds. In the orchards I have seen pruned this way, the orchard’s life expectancy is about 15 years. After that point, too many trees are damaged or broken, and it becomes difficult to farm the variability.
So, is pruning multiple scaffolds (5+) a bad idea? Economically, maybe not. If the increased profits from the early years of tree production are used to pay down long term debt, pruning trees this way can be profitable. I would not recommend this type of pruning for varieties that are upright in nature ( Aldrich, Padre, etc), as they are more susceptible to wind breakage. I have spoken with a few farmers who have said that the risk of tree loss and shortened orchard life are outweighed by the early yields and increased profits. On the flip side, I have also spoken with a few farmers who will never train another orchard with greater than 3-4 scaffolds.
Pruning is an important step in developing a successful orchard. If you are unsure of the style that you want, time should be spent viewing orchards of different training styles. This visualization will help you see what the effects of scaffold selection on tree growth, yield, and orchard practices and hopefully provide the insight that you need to make your training decision.
What are your experiences with the discussed first leaf pruning/scaffold selection?