Training and pruning systems in Europe tend toward obtaining a tree suitable for the high-density orchard.
Such a tree is 6 feet high and has an upright leader tied to a support and numerous weak lateral branches.
In the tree construction, the leader is permanent, while branches are kept temporarily.
These last often are cut away and replaced with young lateral shoots.
This method of pruning enables the tree to easily reach the required size.
The spindlebush form, designed for dense orchards by Schnitz-Hubsh and Heinrichs in Germany in 1936, is currently the most popular training system for dwarf apple and pear trees.
In Holland this system has been gradually modified toward an even slimmer trees called slender spindle and North Holland spindle. Thirty years ago, the standard spindlebush tree was more than 6 feet wide at the base.
Presently, the slender spindle is only 4 feet wide, and North Holland spindle is 3 feet wide.
The very slim tree is obtained by bending the shoot to horizontal and weeping positions by weakening the leader through summer pruning and renewal pruning of lateral branches.
In Germany F. Bumerlin is currently developing a new training system based on slender spindle.
In this new system, called superspindle, dwarf apple trees grafted on M 9, M 27, and P 22 rootstocks are planted at a distance of 8 x 1 foot and trained like a very slim spindle or free cordons.
Trees are not pruned at all for 3 years after planting, so they produce a very early crop, often within 6 months from planting.
Early yield controls the growth.
In France, J.M. Lespinasse has recently designed and promoted a training system for dense orchards called axe centrale. In this system, the leader is stronger and taller (up to 12 feet) than in superspindle.
Lateral branches are also pruned by renewal method; thus, tree width is kept within 3 to 4 feet.
This system seems to be good for densely planted orchards in sunny climates.
Tree training and pruning systems in Europe derive from old practices performed in enclosed gardens.
Fruit gardens were established first in monasteries and castles, especially in the Loire Valley in France.
To best use the space at garden walls or along alleys, trees were planted and trained as palmettes and cordons.
To control tree size and develop the desired shape, pruning was rather severe.
The pruning method used was called taille trigeme (three buds pruning). All annual shoots on a fruiting tree were headed to the third bud from their base to obtain one flower bud, one spur and one shoot for renovation.
It was difficult to achieve the exact distribution of the three types of growth and required skillful gardeners, those who had been able to train the sophisticated forms of fruit trees and prune them.
One of these gardeners, La Quintinye (1626–88), was the head of the fruit and vegetable gardens of King Louis XIV. He wrote a book, published in 1697, Instructions Pour les Jardins Fruitiers et Potagers. The book described the espalier training and pruning systems that were used first in French gardens and later in commercial plantations.
Artificial forms and severe pruning were popular in Europe until the middle of this century.
They were later replaced, mostly with free forms, which need less pruning, but the old tradition still influences actual practices.
There are additional reasons that European tree training and pruning are much different from that performed in United States.
In Europe fruit is grown in small family