Fruit trees: Pruning Terms

These concepts will help with your fruit tree pruning decisions.

• Apical Dominance • Double Leader • Crotch / Crotch Angle 

• Scaffold Branches • Fruiting Wood, Fruit Spurs, Fruit Buds 

• Graft Union • Root Suckers & Watersprouts • Fruiting Arch 

• Branch Collar • Cross Pollination • The Solar Show

Apical dominance

A tree wants to grow up — vertical. Pruning a tree requires you to anticipates this vertical growth, and guide the trees direction through selective pruning.
• Vertical branches / stems exude hormones that suppress growth below.
• A horizontal branch does not suppress vertical growth and multple “watersprouts”, each trying to be the tallest, will erupt vertically from a horizontal branch.
• A branch at a 45º upward angle (approximately) is growing at an angle most ideal for suppressing vertical growth while allowing fruiting wood to develop.

Double leader

Two vertical branches vying for dominance, usually with neither winning, at least not soon enough. Double leader trees are top-heavy and the growth confused. If the bark is included (see Crotch, below), it is almost certain that one of the leaders will break out if allowed to grow too big.

Scaffold branches

The important beginnings of a young tree and the essential structure of the mature tree. Typically three to five branches are allowed to develop around the trunk of the main tree, each getting a slice of sunshine. The selection process begins with a newly planted tree and takes a few years of select pruning and directing. Over time the scaffold branches support major side branches and lessor side branches and fruiting wood. In a fruit tree most all pruning decisions are ultimately based on how to best sustain the scaffold.

Crotch / crotch angle

The angle a branch grows out from another branch. Narrow angles, especially on scaffold / main branches, are to be avoided, eliminated. If the crotch is too narrow, bark becomes “included”, (rather like a permanent "wedgie"). Included bark is probably the most common reason for branch failure; one branch must be eliminated or seriously reduced.

The branch angle can (only) be set early in a branch's development, no later that the beginning of the second year of growth. It is particularly important in the scaffold development of a young tree.

Fruiting wood, fruit spurs, fruit buds

Some buds produce only leaves, and some buds produce flowers. One learns to recognize flower (fruit) buds, what conditions are right for flower bud development, and how to select and manipulate branches into producing fruiting wood, or scaffold branches. Some trees fruit on new growth, on many trees a branch may need to be one or two years old before it grows any flower buds. Learn to recognize which buds are leaf buds and which are flower buds.

Many fruit trees produce short spurs of growth from a branch that ends in a tight cluster of flower buds — this is called a fruit spur. In some fruit tree varieties, a spur can live and be productive for many years; other trees produce fruit spurs that only last a couple of years.

Graft union

Most fruit trees (as well as some other trees and shrubs) are grafted so that the roots are from one tree and the trunk and branches above from another tree. All new vertical shoots (“suckers”) from BELOW the union (i.e. rootside) need to be eliminated. A few rootstocks are very prone to suckering.

Trees can grow on their own roots without a graft, but a graft leads to more consistent results — a more compact tree (or more vigorous, depending), or a tree better suited to soil conditions, etc.
 Branch Collar
When a new side branch grows from another larger branch, it has a swelling at the base called a "collar", where attaches to the main branch.  This collar is an important feature of the main branch.  When you remove a large side branch, try to not damage the branch collar.

Fruiting Arch

The natural tendency for the tip of a branch to be pulled into an arch by the weight of the fruit. Depending upon the tree this can be pronounced and obvious (some plums and apples) to almost non-existent (sweet cherries). Recognizing a trees natural arch can help with pruning decisions.

Cross Pollination

Many fruit trees require pollen from a second variety of the same type of tree in order for there to be fruit set. Some trees are self-fertile, meaning that it can develop fruit from pollen from itself. Trees of self-fertile trees still need to be pollinated, but the bees do not have to visit a second tree.

Some plants have separate male and female plants, or separate male or female flowers on the same plant. However, most fruit trees have “perfect” flowers, each flower having male and female parts in the same flower.

The Solar Show

Leaves on the trees seek light. Leaves still feed a tree with filtered or reflected light, but if a branch is always shaded, it is missing the show.

When choosing what to prune, from time to time face the track of the sun, spread your "branches" in this light, and absorb (imagine) the solar show. Then go back to the pruning the tree.