Basics of fruit tree canopy formation and pruning

The development of trees depends not only on the hereditary properties of the species and cultivar, but also on environmental conditions. By changing these conditions, we thereby compel the fruit plant to change its growth and fruiting patterns and ensure its development in the direction we require.

One of the means that acts strongly and quickly directly on the tree and allows for the regulation of its growth and fruiting is pruning. It began to be used long before people learned how to provide plants with mineral nutrition elements and protect them from pests and diseases.

The first mentions of pruning date back to the 3rd century BC. It was indicated that when growing fruit trees, one should remove dry branches that hinder growth and nutrition. Already at that time, pruning was considered a radical means of regulating growth and fruiting. Thus, Columella, an ancient Roman philosopher and a great expert in agronomy, believed that cultivating a garden is a request, fertilizing it is help, and pruning is forcing trees to fruit. Much of interest about the pruning of fruit trees can be found in the writings of other ancient Roman philosophers – Cato, Varro, and Pliny the Elder.

Correct and timely pruning against the background of good general agricultural practices contributes to:

• an earlier start and rapid increase in fruiting;
• obtaining annual yields optimal for a given cultivar;
• improving fruit quality;
• increasing the frost resistance of trees;
• convenience in performing work during the pruning itself, pest and disease control, and harvesting;
• rational use of the garden's area and space.

Throughout centuries of practice, the technique of pruning has been improved and refined, and new methods for regulating growth and fruiting have been developed. As a result, by the Middle Ages, with the help of this technique, people had learned to create canopy shapes that combined high ornamental value with abundant yield. And yet, pruning still remains one of the most complex issues of agrotechnology. No other plant care measure causes so many disputes and contradictory judgments. The abundance of fruit crops with a large number of cultivars, differing in their growth and fruiting habits, already suggests different plant reactions to the removal of branches or changes in their spatial position. In addition, one should take into account environmental conditions, which do not remain constant year after year, even in the same locality; the condition of the plants, determined by their age, specific operation methods, reaction to temperature conditions, etc.

All of the above forces us to constantly search for the most rational canopy forms and pruning methods that meet modern production requirements and allow the plants' potential capabilities to be manifested to the maximum. It is for this reason that in modern fruit growing there are already not dozens, but hundreds of different training systems, differing in external dimensions, structural composition, the type of growth and fruit-bearing structures, methods of regulating growth and fruiting, and suitability for specific orchard designs.

This chapter outlines the general rules for forming tree canopies applicable for use in organic gardening. It must be remembered that through the shape and structure of the canopy, one can easily influence the final result – the yield and quality of the fruit.

By training system, we mean the creation of a canopy of a specific habit and structure using pruning or other growth regulation techniques.

Each type of canopy has design features, but for most of them, according to V. I. Yakushev and V. I. Shevchenko (1987), there are general rules for formation. The basic principles of forming the canopy of woody fruit plants depend on the design of the orchards and involve the use of various techniques aimed at regulating its shape, size, and productivity.

The goal of formation is to create an easily accessible canopy that is well-illuminated by the sun and capable of providing abundant yields of high-quality fruit at an early age.

The objectives of fruit tree canopy formation in all modern types of plantations are:

• regulating size (i.e., creating compact canopies);
• ensuring the illumination of all parts of the canopy is sufficient for the successful photosynthetic activity of the entire leaf apparatus, as well as for obtaining high-quality, intensely colored fruit;
• increasing canopy strength by spacing first-order branches 10–15, 40–60 cm apart and forming emergence angles of at least 45–60°.

An agronomist, farmer, or beginning hobby fruit grower must be guided by the following principles that underlie the formation of different canopy types:

When planning a garden, it is important to immediately reconcile the type of plantings, the biology of the cultivar, and the shape of the canopy. You cannot prune all trees using the same scheme. For example, if you are establishing an orchard on semi-dwarfing rootstock, the trees will require a larger nutritional area. In this case, form strong primary branches and establish a canopy on them with 3–4 orders of branching.

Planting density directly dictates the architecture of the tree in the garden. The more nursery plants per hectare, the fewer perennial branches should remain in the canopy, since the space for each tree is strictly limited. In such high-density plantings, requirements for the quality and quantity of fruit increase sharply. They must be obtained to the maximum from every square meter of the area occupied by the canopy projection.

Geometry of the correct canopy and care during the growing season

When forming naturally improved (artificially natural) canopies, always adhere to a cone shape. It is important that the base of this cone be filled with more vigorous growth compared to its apex. Lateral shoots on the trunk should have a wide angle of attachment. To ensure that the rows do not shade each other, strictly control the height of the trees.