Pruning is all about helping a tree use the energy it gets from the sun and soil in the most efficient way.
The goal is to grow a few big, healthy, sweet fruits (rather than lots of small, not-so-tasty fruits) and to keep the tree healthy for years to come. When we prune, we:
- Make way for new growth by removing dead branches. “Dead wood” takes energy from the tree that could be going to the thriving branches instead.
- Let sunshine in! Leaves are like little solar panels that power the sugar development in each fruit. If light can’t reach those bottom branches, the fruit won’t develop enough sugar.
- Get air flowing around the tree, which deters disease. Rust fungus and brown rot spores love a moist, dark environment. We don’t love them.
You can’t take a one-size-fits-all approach to pruning. There are lots of factors to consider: What kind of tree is it? Each variety has its own characteristics and growth habits. And the weight of the final crop will be different. What angle is the sun where the tree is planted? That will determine where you need to prune to let the most sunshine in. How strong is the wind in that spot? What makes this particular tree vulnerable and how can we help it be resilient? With more than 60,000 trees, Magana, our tree team leader, and the tree team have their hands full. But with decades of experience, Magana knows each tree in the orchard, its history, and what it needs.
Apricot trees, for example, start getting pruned early, at the end of summer or in the early fall. We prune most other trees in the winter. But apricots are particularly susceptible to a fungal disease called brown rot, which spreads more easily in the rainy later season. If the tree has fresh cuts from pruning, the likelihood that brown rot spores will seep in and infect it is much higher. That’s why we start now—so the cuts can heal before it rains.
And take Flavor King pluots. Compared to other trees, they’re a weak growing variety (but with such delicious fruits!). To make sure they produce new wood and are strong enough for next year’s harvest season, the tree team does a severe winter pruning.
It can be hard to watch. It looks kind of like butchering the tree. But this highly specialized pruning is for the long haul. It ultimately makes the tree healthier. And it makes the soil healthier, too. Everything that’s cut away gets incorporated back into the orchard somehow. Some branches go through our woodchipper and into our compost, which eventually gets spread back through the orchard. Other branches stay right in the middle of the orchard rows, where Umberto comes by with a flail mower and grinds them up into a thick layer of mulch—a great way to retain carbon, nutrients, and water in the ground.
With pruning, you really have to know what you’re doing. How you prune a 1-year-old tree will determine the shape it has for the rest of its life. There’s an art to training an orchard and a lot of scientific knowledge behind it. You need to know how a tree behaves, how it wants to grow, what it needs to thrive, and how to prepare it for how you want to harvest. The Frog Hollow team can’t let a tree grow too tall, for example, or ladders wouldn’t be able to reach the highest fruit!
Farmer Al tells me he learned the art of pruning from Brentwood’s farm advisers, notably Janet Caprille, who mentored him for almost 25 years, and her predecessor, Ross Sanborn. Ross taught a 25-year-old Al the science behind pruning. “When you get taught something like that at that age, you never forget it,” Farmer Al told me. Much like a tree.