Novel sweet cherry system getting attention

A group of tree fruit growers recently got a look at a high-efficiency growing system for sweet cherries called the UFO – short for Upright Fruiting Offshoots.

It was March 1 at Hanrahan Orchards near Yakima, Wash. Busloads of growers on an International Fruit Tree Association tour – part of IFTA’s annual winter conference – watched as grower Mark Hanrahan stood in front of a UFO block and explained how the system works. Hanrahan got some help from Matt Whiting, a fruit physiologist at Washington State University (WSU) who developed the system with help from collaborating growers.

According to IFTA, Hanrahan Orchards encompasses 183 acres: 133 acres of cherries, 24 acres of pears, 12 acres of apples and 12 acres of wine grapes.

Hanrahan told his audience he was looking for a system that was easy to learn and that he could commit to, and UFO seemed to fit the order. He stood in front of a 10 x 9 planting of Early Robin sweet cherries on Gisela 6 rootstock. The planting – 484 trees per acre – is going into its fifth leaf. The ground was fallow for about six years before the planting was put in. Before that, it was Anjou pears, Hanrahan said.

Whiting describes UFO as “a planar system that facilitates precision canopy and fruit management.” It’s a precocious, productive system that has been around for about six years.

Whiting listed some of UFO’s advantages over other systems: It fills space between trees at planting; fruiting walls facilitate the incorporation of new technology (automation and mechanization) for improving labor efficiency and fruit quality; input use is more efficient; the orchard’s environmental footprint is minimized; pruning and training is simplified and systematized; the natural growth habit of the tree is taken advantage of.

He also listed a disadvantage of the system: It’s expensive to establish due to the high tree density and trellising required.
Whiting isn’t sure exactly how many, but growers around the world are using UFO. It’s being planted throughout the United States and also in Chile, Australia, Turkey, Italy and perhaps other countries.

The system was designed for sweet cherries, but pear growers have been trying it out recently. Whiting will be trying UFO with other tree fruit over the next couple of years, he said.

Here’s a brief description of how the system works: When the sweet cherry trees are first put in, they are planted at a slant, bent near horizontal and fastened tight to a trellis wire. Dormant buds are rubbed off the bottom and those left on top become renewable mini-trunks in a solid fruiting wall.

At the end of the first year, the strongest uprights are not headed. Only weak uprights are pruned during the dormant period, leaving a short stub to encourage strong new growth. The upright shoots are encouraged to grow vertically. Laterals that form on the uprights are removed. The idea is to make all of the uprights equally strong and add about 2.5 feet of new growth each year, according to Whiting.

A WSU website (fruit.prosser.wsu.edu/UFO.html) describes the system in more detail:

Pre-planting:
• Work with nursery to deliver un-pruned, un-branched trees
• Tree height should be slightly greater than within-row spacing

At planting:
• Plant trees that are slightly taller than tree spacing (should fill space between trees)
• Plant at 45˚ to 60˚ angle
• Train un-headed whip horizontally
• Focus growth into well-positioned upright buds by bud removal or scoring

First year:
• Promote balanced upright growth
• Summer pinch dominant uprights only
• Clip/tie uprights to second wire
• Dormant pruning unnecessary

Second year:
• Will bear fruit at base of shoots and on spurs not removed at planting
• Do not head uprights, pinch dominant uprights only
• Renew excessively vigorous uprights with dormant stub cuts
• Bearing in the second year
• Second year yields can be up to 2.5 tons/hectare

Third year:
• Harvesting fruit from upright growth of first year
• Summer pinching of dominant uprights
• Upright renewal occurs in dormant season with stub cuts
• Third-leaf yields were 6 to 11 tons/hectare

By Matt Milkovich