Training trees to be short
Though it’s easier to start with young trees, some growers are retrofitting older orchards.
University of California Cooperative Extension’s Kevin Day, a proponent of growing shorter stone fruit trees, has helped numerous growers lower their tree height without diminishing fruit quality or yields. Although initial tree training costs can be higher than those of standard orchard systems, they don’t have to be.
Shorter peach, nectarine, and plum trees (8 to 9 feet tall) can result in significant savings in labor costs—from 10 to 45 percent, depending on the activity—when compared to standard trees 12 to 13 feet tall. But whereas standard orchard systems are left to grow naturally, short trees need wider, flatter angles of 50 to 60 degrees to suppress vigor and help fill the tree space. Tree training and tying down branches can be expensive, ranging from $200 to $300 per acre.
Day said there are various ways to achieve flatter branches, and it can be done inexpensively. While many growers use strings and hop clips to anchor the branches to the ground, some use bamboo and minimal pruning techniques to accomplish flatter branches.
“Some trees are nearly three years old, and they’ve hardly been pruned,” he said. “People think that they open up a tree by pruning the tree hard, but all that’s doing is making the tree more upright. The harder you prune, the more vigorous the tree.”
Though it is much easier to start with young trees and develop the branch angles needed for shorter heights, some growers are having success in retrofitting older orchards, he said. However, the labor-saving benefits may not be as dramatic in retrofitted orchards as in those that were trained from the beginning.