Pruning is reducing trees and branches in size, including removing deadwood.
Pruning includes pollarding and coppicing which keep trees in a managed state of rejuvenation while controlling their size. Crown reductions and crown raising are terms used for pruning the branches which make up the body of the tree as apposed to the trunk.
Pruning fruit trees is undertaken to increase or decrease fruit production as well as the normal tree care reasons of all trees.
Fruit tree pruning is the cutting and removing of parts of a fruit tree. It covers a number of horticultural techniques that control growth, remove dead or diseased wood, and stimulate the formation of flowers and fruit buds. Pruning often means cutting branches back, sometimes removing smaller limbs entirely. It may also mean removal of young shoots, buds, leaves, etc. Careful attention to pruning and training young trees affects their later productivity and longevity. Good pruning and training can 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.
Other sustainable agriculture or permaculture personalities, such as Sepp Holzer and Masanobu Fukuoka, advocate and practiced no-pruning methods.
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 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 begin to thicken to support the plant. On the shoots, these growing tips of the plant are called 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 that otherwise competes with the apical tip for light and nutrients. Removing the apical tip and its suppressive hormone lets lower, dormant lateral buds develop, and the buds between the leaf stalk and stem produce new shoots that compete to become 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 maximize fruit yield. Unpruned trees tend to produce large numbers of small fruits that may be difficult to reach when harvesting by hand. Branches can become broken by the weight of the crop, and the cropping may become biennial (that is, bearing fruit only every other year). Over-pruned trees on the other hand tend to produce light crops of large, flavourless fruit that does not store well. Careful pruning balances shoot growth and fruit production.
Formative pruning of bush fruit trees
In the early years of the tree’s life, it is important to develop a framework sufficiently strong to bear the weight of crops. This requires formative pruning to reinforce the tree. Formative pruning of apple (Malus pumila) and pear (Pyrus communis) trees should be carried out in the dormant winter months. For the Northern hemisphere, this should occur between November and March; For the Southern hemisphere, June and September. Stone fruits—such as cherries, plums, or gages—have different requirements, and should not be pruned in dormant months.
A maiden whip (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.
Remove 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 becomes the tree’s main structural branches. Remove any inward-facing shoots.
Prune 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.
The tree has begun to fruit and requires only limited formative pruning. Shorten leaders by one third and prune laterals not required to extend the framework to four buds.
Five year and onwards
The tree is established, and should be pruned annually as described in the following section.
Pruning the cropping tree
Before pruning, 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 more 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:
- 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 used 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 overcrowded (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 overcrowding 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.
General pruning information, not fruit tree specific.
Pruning is a horticultural and arboracultural practice involving the selective removal of parts of a plant, such as branches roots and buds. Reasons to prune plants include deadwood removal, shaping (by controlling or directing growth), improving or maintaining health, reducing risk from falling branches, preparing specimens for planting and both harvesting and increasing the yield or quality of flowers and fruits. The practice entails targeted removal of damaged, diseased, dead, non-productive, structurally unsound, or otherwise unwanted parts of the tree. Specialized pruning practices may be applied to certain trees such fruit trees. Different pruning techniques may be deployed on herbaceous plants than those used on perennial woody plants. Hedges, by design, are usually (but not exclusively) maintained by hedge trimming rather than by pruning.
Pruning Trees – Fundamental Principles
Trees are very much like human beings in their requirements, mode of life and diseases, and the general principles applicable to the care of one are equally important to the intelligent treatment of the other. The removal of limbs from trees, as well as from human beings, must be done sparingly and judiciously. Wounds, in both trees and human beings, must be disinfected and dressed to keep out all fungus or disease germs. Fungous growths of trees are similar to human cancers, both in the manner of their development and the surgical treatment which they require. Improper pruning will invite fungi and insects to the tree, hence the importance of a knowledge of fundamental principles in this branch of tree care.
All pruning should be commenced at the top of the tree and finished at the bottom. A shortened branch (excepting in poplars and willows, which should be cut in closely) should terminate in small twigs which may draw the sap to the freshly cut wound; where a branch is removed entirely, the cut should be made-close and even with the trunk. Wherever there is a stub left after cutting off a branch, the growing tissue of the tree cannot cover it and the stub eventually decays, falls out and leaves a hole, which serves to carry disease and insects to the heart of the tree. This idea of close cutting cannot be over-emphasized.
Where large branches have to be removed, the splitting and ripping of the bark along the trunk is prevented by making one cut beneath the branch, about a foot or two away from the trunk, and then another above, close to the trunk.
Too severe pruning:
In pruning trees, many people have a tendency to cut them back so severely as to remove everything but the bare trunk and a few of the main branches. This process is known as “heading back.” It is a method, however, which should not be resorted to except in trees that are very old and failing, and even there only with certain species, like the silver maple, sycamore, linden and elm. Trees like the sugar maple will not stand this treatment at all. The willow is a tree that will stand the process very readily and the Carolina poplar must be cut back every few years, in order to keep its crown from becoming too tall, scraggy and unsafe.
Pruning shade trees: Here, the object is to produce a symmetrical crown and to have the lowest branches raised from the ground sufficiently high to enable pedestrians to pass under with raised umbrellas. Such pruning should, therefore, necessarily be light and confined to the low limbs and dead branches.
Pruning lawn trees: Here the charm of the tree lies in the low reach of the branches and the compactness of the crown. The pruning should, therefore, be limited to the removal of dead and diseased branches only.
Pruning forest trees: Forest trees have a greater commercial value when their straight trunks are free from branches. In the forest, nature generally accomplishes this result and artificial pruning seldom has to be resorted to. Trees in the forest grow so closely together that they shut out the sunlight from their lower limbs, thus causing the latter to die and fall off. This is known as natural pruning. In some European forests, nature is assisted in its pruning by workmen, who saw off the side branches before they fall of their own accord; but in this country such practice would be considered too expensive, hence it is seldom adopted.