Mention the word tree felling/removal and immediately you think of cutting down a tree, yet in the field of tree felling there are in fact a wide variety of services offered.
Arborist by the way is a professional tree surgeon in the practice of arboriculture which is the cultivation, management, and study of individual trees, shrubs, vines and other perennial woody plants in dendrology and horticulture.
We thought it would be great to expand on the wide area through this blog and to cover all of the different services that a professional tree feller/arborist actually offers their clients.
Crowning
Crowning is the process where a portion of the smaller branches are removed to produce a density of foliage around an evenly spaced branch structure, and does not shape the overall size or shape of the tree, and within the crowning of a tree you will find that your arborist will mention crown lifting, crown reduction and crown thinning, each of these aimed at a different end result.
Crown Lifting: Here the gap between the ground level and the start of leafy area is increased, normally achieved by removing the lowest branches of the crown to a specific height. Lifting of the tree crown would be applicable when you would want more space around the tree bottom, some may also call this canopy lifting.
A practical example is when a tree obscures a stop street sign and by lifting the crown the sign can be seen.or where more sun is required at the base of a tree. In the picture below as an example the tree base was cleared to provide space for movement below the tree.
Good practice dictates that unless absolutely necessary that large branches growing directly from the trunk should not be removed as this can cause large wounds that can lead to decay of the tree, older mature trees should be avoided or restricted to secondary branches or shortening of primary branches rather than the whole removal where possible.
Crown Reduction: Here the ends of all branches are cut to reduce the overall size of the tree, both in volume and size, whilst still retaining the natural shape of the tree, normally used for aesthetic effect or where the size and volume of the tree may be encroaching on other elements around the tree, such as electric fencing, gutters and others.
Other uses may be to reduce the mechanical stress on a tree due to the size, volume and ultimately weight on the tree due to the growth of the crown area. In the picture below the tree crown was shaped for aesthetic effect using both crown lifting as well as crown reduction.
Crown Thinning: Here the tree feller/arborist will remove some of the branches within the tree crown in order to reduce the density of the tree, the objective being to allow more natural light to pass through the tree or to reduce the wind resistance of the tree, thus allowing for less stress on tree that may be in a windy area. This method is normally used on broad leaved species and does not alter the overall size or shape of the tree.
Good practice will see a gradual removal of inner branches over a period in order to not shock the tree and also it is recommended not to remove more than 30% of the overall structure. It is also rare that this will be done only once on trees with large amounts of epicormic growth, and rather you should prepare to have this done over the life of such a tree. In the picture below it can be seen that the sun is allowed to filter through the branches from an otherwise very densely leafed tree. (Note: Epicormic growth is growth that occurs from dormant sprouts and some tree species produces this growth around wounds caused by pruning)
Tree General
Before we jump into tree pruning it may be worthwhile to cover how a tree actually works, as this will greatly assist in understanding the principles behind pruning.
A tree is in fact a dynamic living organism, with a woody stem that adds the ability to be self supporting. Trees use photosynthesis, which is the process by which plants use sunlight, water and carbon dioxide to create oxygen and energy in the form of sugar, trees uses this sugar to make the building of cellulose (reinforcement material) and lignin (provides trees with rigidity, makes them water resistant and degradation resistant), in order to sustain its self-supporting structure.
These sugars produced are transported throughout the tree via the inner bark area knows as the phloem. The tree roots absorb water and other minerals from the soil, these are transported to the leaves of the tree via tubular vessels called xylem, and in fact this is the vascular tissue, think of it as the pipeline from roots to the leaves.
Branches of trees were once buds that then became twigs, and over time and incremental growth have gone on to form a branch, ultimately a number of these branches forms to provide the tree its unique shape, size and volume.
Pruning
When looking at pruning it is important to understand when to prune as different species react differently to pruning at different periods in the seasons as well as their lifecycle, hence the requirement to arm yourself with knowledge on the trees you may be pruning, or getting the services of a professional tree surgeon/arborist to assist you.
Pruning involves the selective removal of certain parts of the tree and focus is on diseased, damaged, dead and deranged material from the tree, this is also commonly referred to as the "4 D's". Good practice is to start early in the life of a tree as smaller cuts limits the wounds to a tree and starts a healthy process.
Dead Wood Pruning: This is the pruning/removal of dead or dying branches from a tree, this may be for aesthetics, safety or general plant health reasons. These branches may have died due to a number of reasons, such as light deficiency, pest and disease damage, root structure damage and even being planted incorrectly
Formative Pruning: Besides the elaborate designs sometimes seen on especially hedges or dense structured trees and shrubs, formative pruning also assists in reducing risks of diseases, structural weakness and broken branches as trees mature. Formative pruning is especially important in younger trees as they develop to have a balanced shape and structure.
Tree Felling
You may wonder why trees are even removed, as they have such an important role to play in nature, is a living organism and part of nature, yet there are times when it may be the only solution, such as safety, unsuitable for location, visual considerations, impact on environment, diseases or even a tree considered a threat to other trees in area.
Tree felling can be a hazardous exercise and it is strongly recommended to solicit the services of a professional to assist in the removal of a tree, noting that there are also considerations that needs to be taken into account when engaging with tree fellers, such as whether you require the cutting down only of a tree or the stump removal as well, there are considerable efforts and costs with each of these.
If you wish to remove the stump as well there are various methods that could be applied, such as stump grinding, which is a machine that will grind into the stump below ground level, with the wood particles that could be used as mulch, alternatively the Arborist may suggest alternative methods to remove the stump, including the use of herbicides or plain old elbow grease and a few tools to literally chop the stump out of the ground, the only other alternative to use the stump in some creative way.
Besides the requirement for qualified staff and the risks of liability in case of any injuries or deaths as a result of poorly equipped and trained tree fellers, there is also the risk of spreading diseases from infected trees, such as the threat identified by invasive shot hole borer, also referred to as polyphagous shot hole borer (PSHB) – the tiny black beetle, which hails from South-East Asia, has spread to eight of the nine provinces (Limpopo being the only exception), and is the largest geographical outbreak of this beetle in the world, and unethical or uneducated operators that sell or dumps infected wood may do significant damage to environment.
The best way to control these shot-hole borer, or any other bark beetle, remains to cut out the weak branches and remove all dead wood from the area. And by law if these beetles are found by any owner or occupier of land this need to be reported, no person may move, transport or convey a list of 23 targeted tree species, including as firewood and infested wood may not be sold.
The list of Notifiable ISHB Target Trees
Indigenous trees
Coast silver oak (Brachylaena discolor)
Forest bushwillow (Combretum krausii)
River bushwillow (Combretum erythrophyllum)
Coast coral tree (Erythrina caffra)
Water blossom pea (Podalyria calyptrata)
Fountain bush (Psoralea pinata)
Cape willow (Salix mucronata)
Keurboom (Virgilia oroboides subsp. ferruginea)
Exotic trees
Japanese maple (Acer palmatum)
Pink flame tree (Brachychiton discolor)
American sweetgum (Liquidambar styraciflua)
Southern magnolia (Magnolia grandiflora)
Avocado (Pearsea americana)
London plane (Platanus x acerifolia)
Pin oak (Quercus palustris)
English oak (Quercus robur)
White willow (Salix alba)
Invasive species
Blackwood (Acacia melanoxylon)
19. Black wattle (Acacia mearnsii)
20. Chinese maple (Acer buergerianum)
21. Box elder (Acer negundo)
22. Honey locust (Gleditsia triacanthos)
23. Castor-oil plant (Ricinus communis)
Sectional Felling: This is the removal of part of a tree, and practical examples of such a requirement may be trees that overhang onto neighbours properties, trees that branches threaten to damage structures or tree branches that become too heavy to be supported by the three itself, thus only a section of the tree is required to be removed as opposed to the whole tree.
Tree Disease Consulting
Arborists across the country also offers tree disease consulting services, which may include assessment of your soil structures with the aim to have nutrients in the soil that will aid healthy trees and growth in general.
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