Pruning is a horticultural and silvicultural practice involving the selective removal of parts of a plant, such as branches, buds, or roots. Reasons to prune plants include deadwood removal, shaping (by controlling or directing growth), improving or maintaining health, reducing risk from falling branches, preparing nursery specimens for transplanting, and both harvesting and increasing the yield or quality of flowers and fruits. The practice entails targeted removal of diseased, damaged, dead, non-productive, structurally unsound, or otherwise unwanted tissue from crop and landscape plants. Specialized pruning practices may be applied to certain plants, such as roses, fruit trees, and grapevines. It is important when pruning that the tree’s limbs are kept intact, as this is what helps the tree stay upright. 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 landscape and amenity trees
For arboricultural purposes the unions of tree branches (i.e. where they join together) are placed in one of three types: collared, collarless or codominant. Regardless of the overall type of pruning being carried out, each type of union is cut in a particular way so that the branch has less chance of regrowth from the cut area and best chance of sealing over and compartmentalising decay. This is often referred to by arborists as “target cutting”.
Branches die off for a number of reasons including light deficiency, pest and disease damage, and root structure damage. A dead branch will at some point decay back to the parent stem and fall off. This is normally a slow process but can be quickened by high winds or extreme temperature. The main reason deadwooding is performed is safety. Situations that usually demand removal of deadwood is trees that overhang public roads, houses, public areas and gardens. Trees located in wooded areas are usually assessed as lower risk but assessments consider the amount of visitors. Usually, trees adjacent to footpaths and access roads are considered for deadwood removal.
Another reason for deadwooding is amenity value, i.e. a tree with a large amount of deadwood throughout the crown looks more aesthetically pleasing with the deadwood removed. The physical practice of deadwooding can be carried out most of the year though not when the tree is coming into leaf. The deadwooding process speeds up the tree’s natural abscission process. It also reduces unwanted weight and wind resistance and can help overall balance.
Crown and canopy thinning
Crown and canopy thinning increases light and reduces wind resistance by selective removal of branches throughout the canopy of the tree. This is a common practice which improves the tree’s strength against adverse weather conditions as the wind can pass through the tree resulting in less “load” being placed on the tree. The shape is vital for the survival of the tree and lopping off the wrong sections of a tree if it has surpassed its height limit can actually be extremely damaging. This can hinder its growth or cause an overbalance.
Crown canopy lifting
Crown lifting involves the removal of the lower branches to a given height. The height is achieved by the removal of whole branches or removing the parts of branches which extend below the desired height. The branches are normally not lifted to more than one third of the tree’s total height.
Crown lifting is done for access; these being pedestrian, vehicle or space for buildings and street furniture. Lifting the crown will allow traffic and pedestrians to pass underneath safely. This pruning technique is usually used in the urban environment as it is for public safety and aesthetics rather than tree form and timber value.
Crown lifting introduces light to the lower part of the trunk; this, in some species can encourage epicormic growth from dormant buds. To reduce this sometimes smaller branches are left on the lower part of the trunk. Excessive removal of the lower branches can displace the canopy weight, this will make the tree top heavy, therefore adding stress to the tree. When a branch is removed from the trunk, it creates a large wound. This wound is susceptible to disease and decay, and could lead to reduced trunk stability. Therefore, much time and consideration must be taken when choosing the height the crown is to be lifted to.
This would be an inappropriate operation if the tree species’ form was of a shrubby nature. This would therefore remove most of the foliage and would also largely unbalance the tree. This procedure should not be carried out if the tree is in decline, poor health or dead, dying or dangerous (DDD) as the operation will remove some of the photosynthetic area the tree uses. This will increase the decline rate of the tree and could lead to death.
If the tree is of great importance to an area or town, (i.e. veteran or ancient) then an alternative solution to crown lifting would be to move the target or object so it is not in range. For example, diverting a footpath around a tree’s drip line so the crown lift is not needed. Another solution would be to prop up or cable-brace the low hanging branch. This is a non-invasive solution which in some situations can work out more economically and environmentally friendly.
Directional or formative pruning
Removal of appropriate branches to make the tree structurally sound while shaping it.
Selectively pruning a window of view in a tree.
Reducing the height and or spread of a tree by selectively cutting back to smaller branches and in fruit trees for increasing of light interception and enhancing fruit quality.
A regular form of pruning where certain deciduous species are pruned back to pollard heads every year in the dormant period. This practice is usually commenced on juvenile trees so they can adapt to the harshness of the practice.
Types of pruning
Removing a portion of a growing stem down to a set of desirable buds or side-branching stems. This is commonly performed in well trained plants for a variety of reasons, for example to stimulate growth of flowers, fruit or branches, as a preventative measure to wind and snow damage on long stems and branches, and finally to encourage growth of the stems in a desirable direction. Also commonly known as heading-back.
- Thinning: A more drastic form of pruning, a thinning out cut is the removal of an entire shoot, limb, or branch at its point of origin. This is usually employed to revitalize a plant by removing over-mature, weak, problematic, and excessive growths. When performed correctly, thinning encourages the formation of new growth that will more readily bear fruit and flowers. This is a common technique in pruning roses and for amplifying and “opening-up” the branching of neglected trees, or for renewing shrubs with multiple branches.
- Topping: Topping is a very severe form of pruning which involves removing all branches and growths down to a few large branches or to the trunk of the tree. When performed correctly it is used on very young trees, and can be used to begin training younger trees for pollarding or for trellising to form an espalier.
- Raising: Removes the lower branches from a tree in order to provide clearance for buildings, vehicles, pedestrians, and vistas.
- Reduction: Reduces the size of a tree, often for clearance for utility lines. Reducing the height or spread of a tree is best accomplished by pruning back the leaders and branch terminals to lateral branches that are large enough to assume the terminal roles (at least one-third the diameter of the cut stem). Compared to topping, reduction helps maintain the form and structural integrity of the tree.
In orchards, fruit trees are often lopped to encourage regrowth and to maintain a smaller tree for ease of picking fruit. The pruning regime in orchards is more planned and the productivity of each tree is an important factor.
Deadheading is the act of removing spent flowers or flowerheads for aesthetics, to prolong bloom for up to several weeks or promote rebloom, or to prevent seeding.
Pruning small branches can be done at any time of year. Large branches, with more than 5-10% of the plant’s crown, can be pruned either during dormancy in winter, or, for species where winter frost can harm a recently pruned plant, in mid summer just after flowering. Autumn should be avoided, as the spores of disease and decay fungi are abundant at this time of year.
Some woody plants that tend to bleed profusely from cuts, such as maples, or which callous over slowly, such as magnolias, are better pruned in summer or at the onset of dormancy instead. Woody plants that flower early in the season, on spurs that form on wood that has matured the year before, such as apples, should be pruned right after flowering, as later pruning will sacrifice flowers the following season. Forsythia, azaleas and lilacs all fall into this category.
Grubbing can make it possible to shred a part or a whole stump and its roots, while it is still in the ground. The whole thing is done without “pulling” the stump, which keeps the environment intact without deteriorating the immediate environment or the underground networks near the stump.
Whether for esthetics, redevelopment, safety or to prevent new growth, grubbing is a complement to slaughter.
Fruit Tree Trimming
Although the principles of the size of fruit trees remain unchanged, practices used in fruit tree cultivation have varied over the years. Still today, even in high density orchards, the driving systems adopted by tree growers are based on these same principles. Before applying a specific management system to a high density orchard, it is advisable to thoroughly examine the size and training techniques of this system.
The size has a dwarfing effect on the tree
Many experiments show that size is a nanning process, that is, it reduces the height and size of the tree.
The size seems to give vigor to the tree
The effects of pruning are somewhat misleading, as vigorous shoots and large leaves soon emerge very close to the wounds of size. One might therefore think that the growth of the tree is accelerated. In fact, the size decreases the number of points of growth stimulating thus those that remain
Size produces localized effects
The total suppression or pruning of the branches of a branch reduces the growth of this branch. The size favors growth in the part of the cut.
Too severe size has various negative effects
The size, when too severe, by stimulating the growth to excess, causes a lack of coloring of the fruits, delays their maturation and favors the growth of suckers and rejections.
The size of the young trees delays the fruit setting
When new fruit trees are harvested from a nursery, many of the finer roots are destroyed. The balance between leaves and roots no longer exists, the young tree now has more leaves than the root system can feed. The result is an imbalance that will delay the growth of the tree.
Size and formation at planting
The smaller the size during this period, the earlier the tree will bear fruit early in the season. This is why it is necessary to make the minimum size once the carpenter branches have been selected until the tree bears fruit.
Formation of young non-fruit trees
Moins on taille pendant cette période, plus l’arbre porte des fruits tôt dans la saison. Voilà pourquoi il faut faire le minimum de taille une fois que les branches charpentières ont été sélectionnées jusqu’à ce que l’arbre porte des fruits
Size of adult trees
Size in period of dormancy
Trees are mostly sized, especially when they are dormant, from when the leaves fall in late autumn to when buds begin to swell in early spring. The ideal and safest time is before the swelling of the buds.
Any size has a dwarfing effect, but size during dormancy is the one that most favors vegetative growth. If one wants to obtain a new vegetative thrust, the size in period of dormancy is the best way to do it.
Planting a new fruit tree is always a joy for a gardener. After visiting the nurseryman or at a planting party, or at the arrival of the package, we hurry to plant his tree in the garden. We install it in its planting hole (with a handful of nettles?), It is wired, it is watered, we rejoice in thinking about the future crops and the jams and preserves that will follow … forget it.
Three or four years later, the small tree grew well and it is the pride of its owners, delighted to see it grow so well … Depending on the case (see below), it has become quite bushy or on the contrary its branches Are lengthened inordinately. The first crop occurs and suddenly, due to a lack of appropriate training size, things will begin to get complicated. Indeed, as it has developed naturally, the tree is badly prepared to carry heavy crops and these will damage it year after year. The situation is very different according to the vegetative mode of the trees, but in all cases a well-conducted training size avoids most of these problems. By ‘training size’, as opposed to fruiting size, maintenance size or regeneration size, is meant the size carried out during the first years of a tree and which aims to establish its framework well.