Short trees require more work up front
But labor savings and productivity are long-term benefits.
Grower Paul Muradian has nearly ten years of experience with tight tree spacing and multiple leader orchard systems in peach and nectarine orchards. But though they are very productive and pedestrian-friendly, he worries about the economics and labor needed to establish and to sustain such high-management systems.
Muradian farms about 200 acres of fresh-market peaches and cling peaches for processing, as well as plums, Pluots, nectarines, and grapes with his brother in Kingsburg, California. He has some of the earliest nectarines in the San Joaquin Valley, which he attributes to a combination of site and variety selection. Several blocks of plums and peaches are certified organic, with additional acreage in transition for organic certification.
In an effort to reduce labor costs—which he said in cling peaches accounts for 70 percent of inputs—he is focusing on making his trees smaller. Although ladders are needed, most workers only need to climb the first two or three steps to thin, pick, or prune in the Muradian orchards.
His experience with nontraditional peach training systems began in the 1990s when he bought a cling peach orchard with 12-foot-wide rows and 8 feet between trees. The cling peach trees were trained to a palmette system and grown as a hedge. Since then, he has planted his peach and nectarine trees in different spacings, but found that 16-foot rows with 10 to 12 feet between trees works best for trees trained with four to six leaders in an open vase type system. His spacing is much tighter than conventional orchards planted with 18-foot rows and trained to the two-leader Kearney-V (vase) system.
“The 16 by 10 or 12 [feet] is the most productive of any tree fruit spacing for soft fruit,” he said, “but you need good light management for that spacing.”
Muradian believes that tighter-spaced orchards pay off in the long term, because there are fewer open spaces than there are in conventional orchards when limbs are lost. However, he said he must produce about two tons more fruit to pay for the extra management involved in the tight spacing.
“In cling peaches, it works,” Muradian said, adding that while the statewide average production for cling peaches is around 13 tons per acre, he regularly picks up to 25 tons per acre.
He has found that smaller, one-year hanger wood is just as good as top wood, and he is able to pick large fruit from the bottom of the trees in the four to six leader systems.
He uses mechanical topping in the summer and now combines some pruning steps. “I found that by waiting until after harvest to remove suckers, the workers can prune everything, and I can save one pass. I’m doing my winter pruning now,” he said during an interview in late September.
Muradian notes that tree training involved in the four- and six-limb vase system is expensive because limbs must be tied to the ground during the early years of the tree to develop branch angles of 50 to 60 degrees. Flatter and wider branches are needed for fruit-bearing efficiency. In standard plantings, limb tying is not necessary because natural branch angles of around 65 degrees are used.
“It is labor intensive to set it up, and you have to have a light management and shading plan,” he said. “You don’t want to get in there to prune too early or you’ll get limb burn.”
Worker education is very important because most workers are unfamiliar with pruning a six-scaffold tree. Uniform limb placement is important to reduce tree variability and simplify pruning for workers. “They know the regular vase-shaped tree, but this is more complicated.”
And while he has planted several blocks with tighter spacings in a pedestrian-friendly orchard system, nonetheless, he is considering going back to the wider 18-foot-by-18-foot spacing in some of his future plantings, because he believes the wider plantings require less management and expense.
“If you are paying by the hour, a six-limb tree works best,” he said. “But workers really prefer to do piece work. I lost workers this season that I was paying hourly to jobs that were paying piece rate. You can’t have everything closely planted because I don’t think we will have the labor to sustain it.” Muradian adds that growers must balance the one or two years of tree training costs and pruning differences between conventional and short tree orchard systems with the long-term savings in labor due to reduced use of ladders.