The essentials of pruning

The pruning of fruit trees is a simple form of tree manipulation, yet many farmers overcomplicate the practice. Horticultural consultant Dr Nigel Cook explains to Glenneis Kriel how to maximise the value of pruning.

- Glenneis Kriel

FAST FACTS

Heading and thinning are the main forms of pruning used on any type of tree.

The aim of pruning is to manage tree structure and light within the tree canopy, as well as the bearing positions of buds.

Pruning always has a dwarfing effect, which affects the roots of the plant in particular.

Pruning is not rocket science; the fundamentals were established in the 1890s and research has produced few real insights on the subject since then. Yet it is often misunderstood or seen as more complex than it is, says Dr Nigel Cook, founder of horticultural consultancy Prophyta.

This is either because farmers do not understand the basics of pruning or confuse it with other forms of tree manipulation, of which pruning is a subdivision.

Another reason is the multitude of words used for the same technique. In reality, only two techniques are used on all trees and shrub whether citrus, pome, stone fruit or berries.

• Heading Also referred to as topping, this refers to the practice of decapitating the top part of a shoot, branch or tree.

• Thinning This practice refers to the removal of entire side shoots or branches (see illustration).

These techniques cause two very different physiological responses in the tree, says Cook.

HEADING VS THINNING

Cutting the top part of a shoot, branch or tree disturbs apical dominance, sparking a complex hormonal reaction within minutes. This leads to increased vegetative growth and reduced fruiting for up to two years. This reaction has even been noted on moss that has been eaten by snails.