Fruit tree pruning

This article is about pruning of fruit bearing trees. For the pruning of trees and other plants in general, see Pruning.

A community apple orchard originally planted for productive use during the 1920s, in Westcliff on Sea (Essex, England), illustrating long neglected trees that have recently been pruned to renew their health and cropping potential

Pruning fruit trees is a technique that is employed by arboriculture to control growth, remove dead or diseased wood, and stimulate the formation of flowers and fruit buds. Pruning often means cutting branches back to laterals or back to the main stem using proper pruning techniques. It may also mean the removal of shoots (including stems), buds, leaves, etc. The most effective pruning is done early in the spring season, when buds begin to break and the soft tissue can be pinched off with just the fingers (hence the expression "nipped in the bud"). Many arborists follow the concept of "harvesting the sun" when pruning fruit trees. Many homeowners make the mistake of planting a fruit tree, then neglecting it until it begins to bear fruit. Careful attention to pruning and training young trees will ultimately determine their productivity and longevity. Good pruning and training will also prevent later injury from weak crotches (where a tree trunk splits into two or more branches) that break from the weight of fruit, snow, or ice on the branches.

Overview

An apple tree sprout is being converted to a branched, fruit-bearing spur by an arborist. Numbers show the sequence of cuts, which occurred during two years.

To obtain a better understanding of how to prune plants properly, it is useful to have some underlying knowledge of how pruning works, and how it affects the way in which plants grow.

Plants form new tissue in an area called the meristem, located near the tips of roots and shoots, where active cell division takes place. Meristem growth is aimed at ensuring that leaves are quickly elevated into sunlight, and that roots are able to penetrate deeply into the soil. Once adequate height and length is achieved by the stems and roots, they will begin to thicken to give support to the plant. On the shoots, these growing tips of the plant are known as apical buds. The apical meristem (or tip) produces the growth hormone auxin, which not only promotes cell division, but also diffuses downwards and inhibits the development of lateral bud growth which would otherwise compete with the apical tip for light and nutrients. Removing the apical tip and its suppressive hormone allows the lower dormant lateral buds to develop, and the buds between the leaf stalk and stem produce new shoots which compete to become the lead growth.

Manipulating this natural response to damage (known as the principle of apical dominance) by processes such as pruning (as well as coppicing and pollarding) allows the Arborist to determine the shape, size and productivity of many fruiting trees and bushes. The main aim when pruning fruit trees is usually to obtain a decent crop of fruit rather than a tree with an abundance of lush yet unproductive foliage. Unpruned trees tend to produce large crops of small, worthless^{[citation needed]} fruit often damaged by pests and diseases, and much of the crop is out of reach at the top of the tree. Branches can become broken by the weight of the crop, and the cropping may become biennial (that is, only bearing fruit every other year). Overpruned trees on the other hand tend to produce light crops of large, flavourless fruit that does not store well. Pruning is therefore carried out to achieve a balance between shoot growth and fruit production.

Formative pruning of bush trees

During the early years of the tree's life, it is important to develop a framework that is sufficiently strong and capable of bearing the weight of crops borne. In order to reinforce the tree, formative pruning should be carried out.

Formative pruning of apple (Malus pumila) and pear (Pyrus communis) trees should be carried out during the dormant winter months. For the Northern hemisphere, this should occur between November and March; For the Southern hemisphere, June and September.

The pome and stone fruits—such as cherries, plums, or gages--have different requirements and should not be pruned during their dormant months.

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  One year old tree

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  Two year old tree

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  Three year old tree

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  Four year old tree

Maiden tree

A maiden whip (that is, a one year old tree with no side shoots) should be pruned to a bud with two buds below it at about 80 cm from the ground immediately after planting to produce primary branches during the first growing season. A feathered maiden (that is, a one year old tree with several side branches) should have its main stem pruned back to three or four strong shoots at 80 cm from the ground. Side shoots should be shortened by two thirds of their length to an upward or outward facing bud. Lower shoots should be removed flush with the stem.

Two year

Remove any lower shoots and prune between three and five of the best placed shoots by half to an upwards or outwards facing bud to form what will become the tree's main structural branches. Remove any inwards facing shoots.

Three year

Prune the leading shoots of branches selected to extend the framework by half to a bud facing in the desired direction. Select four good laterals to fill the framework and shorten these by a half. Prune any remaining laterals to four buds to form fruiting spurs.

Four year

The tree will have begun to fruit and only limited formative pruning is now required. Shorten leaders by one third and prune laterals not required to extend the framework to four buds.

Five year and onwards

The tree is considered to be established and should be annually pruned as described in the following section.

Pruning the cropping tree

Spur pruning

Before pruning it is important to distinguish between spur bearing varieties, tip bearing varieties, and an intermediate between the two that bears both on spurs and at the tips. Spur bearing trees occur much less frequently than tip bearing trees, and they bear most of their fruit yearly at the end of short lateral pieces of wood (spurs) up to about 4 inches long. Spur bearing types include apples of the varieties Cox's Orange Pippin, James Grieve and Sunset, and pears such as Conference, Doyenne du Commice and Williams Bon Chretien. Tip bearers on the other hand produce most of their fruit buds at the tips of slender shoots grown the previous summer, and include the apples Worcester Pearmain and Irish Peach, and the pears such as Jargonelle and Josephine de Malines. There are basically three types of pruning that are applied once the main shape of the tree has been established. These are:

Renewal pruning

• Spur pruning:Spur bearing varieties form spurs naturally, but spur growth can also be induced.
• Renewal pruning: This also depends on the tendency of many apple and pear trees to form flower buds on unpruned two year old laterals. It is a technique best utilised for the strong laterals on the outer part of the tree where there is room for such growth. Pruning long neglected fruit trees is a task that should be undertaken over a lengthy period, with not more than one third of the branches that require removal being taken each year.
• Regulatory pruning: This is carried out on the tree as a whole, and is aimed at keeping the tree and its environment healthy, e.g., by keeping the centre open so that air can circulate, removing dead or diseased wood, preventing branches from becoming over crowded (branches should be roughly 50 cm apart and spurs not less than 25 cm apart along the branch framework), and preventing any branches from crossing.

Pruning of tip bearers

Tip bearers should be pruned lightly in winter using the regulatory system (see above). any maiden shoots less than 25 cm in length should be left untouched as they have fruit buds at their tips. Longer shoots are spur pruned to prevent over-crowding and to stimulate the production of more short tip bearing shoots the following year. Branch leaders are 'tipped', removing the top three or four buds to a bud facing in the desired direction to make them branch out and so produce more tip bearing shoots.

The no pruning option

The no-pruning option is usually ignored by fruit experts, though often practised by default in people's back gardens! But it has its advantages. Obviously it reduces work, and more surprisingly it can lead to higher overall yields.

—Patrick Whitefield, How to make a forest garden p16

Masanobu Fukuoka as part of his early experiments on his family farm in Japan experimented with no pruning methods, noting that he ended up killing many fruit trees by simply letting them go which resulted in convoluted and tangled, and thus unhealthy, branch patterns. Then he realised this is the difference between natural-form fruit trees and the process of change of tree form resulting from abandoning previously-pruned unnatural fruit trees. He concluded that the trees should be raised all their lives without pruning which would allow them to form healthy and efficient branch patterns following their natural inclination. This is part of his implementation of the Tao-philosophy of Wú wéi translated in part as no-action (against nature), and he described it as no unnecessary pruning, nature farming or "do-nothing" farming, of fruit trees, distinct from non-intervention or literal no pruning. He ultimately achieved yields that were comparable to or exceeded standard/intensive practices of using pruning and chemical fertilisation.

Other sustainable agriculture or permaculture advocates have also practiced no-pruning methods with success. Sepp Holzer has successfully used no-pruning methods on his high altitude farm in the Austrian Alps, noting that under heavy winter snow loads, short pruned branches will break often killing the tree, but longer unpruned branches will bend down and touch the ground thus giving them another point of support and preventing breakage.

See also

• Arboriculture
• Fruit tree forms
• Fruit tree pollination
• Fruit tree propagation
• Orchards

External links

• Alabama Cooperative Extension Video on Pruning Fruit Trees (1 of 3) [1]
• Fruit Tree pruning diagrams

"One straw revolution website". http://www.onestrawrevolution.net/MasanobuFukuoka.htm.