The thickness of the fruit wall is maintained by mechanical pruning performed annually six or seven weeks after bloom, as shown in the photo of a Granny Smith planting
|The fruit wall system was developed in France by the Centre Technique Interprofessionnel des Fruits et Légumes to enhance the technical, economic, and environmental performance of apple orchards. The fruit wall makes greater use of mechanization and modifies the design of apple orchards.
A fruit wall is a fruit hedge with a two-dimensional surface. Winter pruning is replaced by mechanical pruning in summer. The narrow hedge allows for fruit to grow on both sides, which is conducive to mechanization.
In 1988, Alain Masseron, the Ctifl engineer in charge of the orchard management program at the Lanxade research station, implemented the first fruit wall trial. In his project, he used a fan-shaped tree to create a narrow fruit hedge that would be more compatible with use of the Magali robot. Masseron felt that since harvesting was mechanized, Ctifl should develop a method of mechanical pruning for fruit trees. He and his technician Laurent Roche conducted several experiments with mechanized pruning, which ultimately led to the development of the fruit wall concept.
Development of the Magali robot was suspended in France in 1996 due to the high costs of the robot and its incompatibility with French orchards. Nevertheless, in light of the promising initial results, Ctifl decided to pursue work on the fruit wall. In 1999, the first French fruit wall orchards were established in the Val de Loire region. Growers converted existing orchards formerly managed under the central leader system into fruit wall systems, with mixed results.
In 2001, new orchards were established as fruit walls from the time of planting as whips. Finally, in 2003, Ctifl, with the participation of nurseries, introduced a new preshaped nursery plant called the Upsilon, with at least two leaders, to increase fruit set and yield, and reduce planting costs.
Today, the fruit wall system is used in more than 1,000 hectares (2,500 acres) of dessert apple orchards and 3,500 hectares (8,650 acres) of cider apple orchards. Every year, new orchards are established to mechanize French production and offset the country’s high labor costs. Elsewhere in Europe, the first fruit wall orchards have been planted in Spain, and trials are under way in Belgium and Germany.
Trees in each row should be spaced according to variety, rootstock, soil fertility, and tree shape. The recommended distances for vertical axis-trained fruit walls range from 0.75 to 1.25 meters (2.5 to 4.0 feet), and from 1.25 to 2 meters (4.0 to 6.5 feet) for the fan-shaped trees. Trees must be well developed at the time of planting.
The establishment of a fruit wall orchard calls for a robust trellis system with four or five wires. The recommended spacing between posts is 6 to 8 meters (20 to 26.5 feet).
In late summer, the induction of buds on shoots, or brindles tipped with buds, may be observed.
During the winter, additional pruning is done to remove forgotten branches, branches that compete with the central leader, and frail or collapsed branches.
The producing area per hectare of a fruit wall orchard must range from 13,000 to 17,000 square meters (58,000 to 74,000 square feet per acre) in order to achieve yields comparable to those of a central leader system. The producing area depends on the planting distances and the producing height of the fruit hedge.
The average number of fruits per square meter per side is 25, plus or minus three fruits depending on the variety and the marketing objectives. That’s equivalent to about 2.5 fruit per square foot.
To boost the yield, it is the producing area per hectare, not the number of fruits per square meter, that must be increased.
However, it must be noted that fruit is less visible on the fruit wall, which generally leads to underestimates of production. For this reason, growers use a square-meter template placed against the fruit hedge to determine the fruit load.
Varieties managed under a fruit wall system are more sensitive to chemical thinning than those managed under a central leader system. Moreover, the fruit wall is well suited to the use of new equipment such as the Darwin string mechanical thinner and postbloom thinning with "tree shakers."
The fruit wall concept facilitates access by equipment and workers in the orchard. It dispenses with the need for skilled orchard workers and allows newly hired personnel to be trained quickly.
Every year, the fruit wall saves between 80 and 100 hours per hectare (32 to 40 hours per acre) of pruning time. It reduces thinning and picking time and facilitates other manual work.
The development of a fruit wall demands investments in new tree equipment, and tools for trimming, thinning, and harvesting.
The greatest difficulty lies in thinking according to the fruit wall concept and adapting working methods accordingly.
Since the success of the fruit wall concept in apple orchards, new trials are under way in France, primarily on cherry, Japanese plum, and peach.