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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 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

Alain Masseron, Laurent Roche, and Sandrine Codarin, CTFIL, France

 

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.

How it began

In 1986, Ctifl began a survey of management systems with the aim of cutting fruit-growing costs. At the time, two companies had begun working on a project to harvest fruit using a robot called Magali. Accordingly, Ctifl made adapting the orchard to the use of the ­Magali robot one of the objectives of its study.

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.

Planting

As with central leader systems, it is recommended that fruit walls be planted on good production sites with rows running along a north-south axis, and that the trees be managed to encourage vigorous growth in the early years. The main commercial varieties of apple grown in the world today are suitable for the fruit wall management system. For dessert apples, the most commonly used rootstocks are the vigorous Malling 9 clones (Pajam 2 or EMLA 9). Rows in a fruit wall system should be planted 3.5 meters (11.5 feet) apart. Wider spacings lead to lower yield per hectare, whereas narrower ­spacings require special tree equipment.

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).

Trimming

The fruit wall is a maximum of 80 centi­meters (32 inches) wide at the base of the tree and 60 centi­meters (24 inches) at the top (see "The fruit wall" ). The thickness is maintained each year by mechanical pruning called trimming. This operation is performed annually six or seven weeks after bloom when 12 well-developed leaves are observed on the shoots of the year (not counting the very first rosette of leaves). Trimming begins in the second year after planting, if the trees exhibit good vegetative growth, and takes two to three hours per hectare per year.

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.

Yield

The potential yield of the fruit wall is regulated by the producing area (on both sides of the fruit hedge) and the number of fruits per square meter.

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.

Advantages

The fruit wall concept is well suited to all apple varieties. It allows for the production of a similar quantity and quality of fruit (size, color, and eating quality) as from central leader systems. However, the size and color of the fruits are more uniform.

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.

Drawbacks

The establishment cost of a fruit wall orchard is often higher than that of an orchard with a central leader system because it requires more extensive trellising.

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.

Outlook

The fruit wall concept takes fruit growing one step farther on the road to mechanization. It reduces production costs and employs the sustainable production methods (such as new thinning techniques) desired by growers and consumers alike.

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.