Arborfield Tree Care are qualified tree surgeons across Berkshire, Hampshire and Surrey. We pride ourselves on providing beautiful and healthy trees. We offer comprehensive treatments to cover tree crowns.
Tree Crown Reduction
This is the process of removing branch tips, in effect pruning back to a growth point further down the branch. Crown reduction is necessary to reduce the overall size of a tree but with the aim of keeping its main shape from which the new growth can sprout. The basic shape of the tree is therefore maintained, but the overall size of the tree is significantly reduced. Performing a crown reduction is a very effective way of maintaining potentially large trees that are close to buildings or roads. Many double decker bus routes that are lined with large trees across Berkshire, Hampshire and Surrey have benefited from tree crown reduction treatment.
There are many reasons for performing a crown reduction mostly the reason is simply to allow more sunlight into the owner´s property but other reasons include:
- To remove dead, diseased or damaged branches.
- To reduce the overall size of the tree.
- To reduce the growth of the tree´s root system that can in turn cause damage to footpaths, roads, patios and walls.
- To deal with maturing trees where the root system has had significant decay making it potentially hazardous.
- To restore the tree´s crown to a safe size avoiding the potential of storm damage in high wind and snow.
- To reduce the overall weight of a leaning tree to reduce the chance of tree failure.
There can be a limit to the extent that a tree crown of an individual tree may be able to be reduced. This is in particular dependent on the location of the tree and the species. These along with other factors can influence the number of growth points that may be available when pruning back the tree crown. The removal of the foliage during tree crown reduction is not considered to be good practice as this can shock the tree into growing back at a faster and from additional points along the branches creating defects in the future. Crown reductions should be undertaken to BS3998:200 by trained and qualified Arboriculturalists and not exceed reasonable amounts. A maximum of 30% of any tree´s crown should be reduced at any one time to reduce the chance of ill health to the tree. The optimum time of the year to carry our reductions to deciduous trees is during their dormant season (Winter in the UK). However depending on the time of year or due to other factors, reducing the tree crown while in full leaf may become necessary. This should be avoided if possible as a rule, however it is worth noting that this does not always harm the tree if treatment is required.
Tree Crown Thinning
Crown thinning is a great alternative to a crown reduction and often much cheaper too.
Crown thinning maintains the natural growth cycle but allows light to pass through the low overall density of the crown or tree canopy. Crown thinning is generally carried out when a tree is located in such a site that size is not an issue but general upkeep is needed to maintain good health.
Tree crown thinning involves removing a number of branches in such a way that it produces a healthy balanced crown structure without altering the overall shape and size of the tree. Crown thinning is applied mainly to broad leaf tree species and commonly amongst fruit trees. This is achieved by removing an overall percentage of the density of the tree´s crown starting with removing all dead, diseased, and crossing branches and then if more of the tree´s mass is needed to be removed, we will remove branches from overcrowded areas of the crown to achieve a clean and safe tree that retains its natural beauty and will thrive for many more years to come
Branches are removed from within the tree crown in order to make it uniformly less dense. The natural shape of the tree is completely unaffected but the ‘Sail Effect’ (wind resistance) is reduced and more light allowed to filter through. This procedure is usually stipulated in terms of a percentage, rarely more than 30%.
Tree Crown Lifting
Tree crown lifting involves the removal of lower branches with the end result being to lift the overall height of the crown base. Crown lifting is carried out to increase the clearance between the ground level and the lower branches either to allow access below the tree, to clear the sight lines, improve views or allow light to penetrate to the ground underneath the branches.
By removing the lower branches you can:
Allow access to areas beneath the tree, especially for vehicles. The Highway Code states that the clearance must be 5.2 meters and 2.5 meters above a footpath.
- To help keep them away from a buildings by creating a lower crown
- To keep away from traffic
- To remove interference from structures, fences, properties and telephone lines.
- To make signs visible that were installed too far off the ground
- To let in more light or improve light levels
- To open up a desirable view and aesthetically enhance the tree
- To create a lower trunk free of branches.
Crown lifting in older mature trees should be restricted to secondary branches. This will minimize stress and reduce the recovery time. BS3988:2010 recommends that crown lifting is restricted to no more that 15% of the current lift to the crown height in order to leave the crown two thirds of the total height of the tree. If you are unsure about how much lift to the tree crown, contact us for a free no obligation site survey from our experienced tree surgeon.
What is the Potential Damage of Crown Lifting?
A trunk could be seriously injured if too many lower branches are removed at any one time. We will work with you and advise the best course of action using our many years of experience.
Possible problems to the tree could occur including:
- Discolouration to the wood
- Possible decay may begin inside the trunk of an over pruned tree.
- Removing too many lower branches can result in sunburn on the lower trunk
- Can result in epicormic growth which forces the tree to grow taller.
What is the Ideal Solution for Crown Lifting?
Ideally half the foliage should originate from branches on the lower two thirds of the tree. Some major branches should be left on the lower half of the trunk.
We try to leave small branches on the lower trunk intact for about a year or more if possible after removing large branches because they help minimize injury from sudden sun exposure by shading the trunk. They also speed closure of pruning wounds.
Thin or drop crotch cut the largest branches in the lower part of the tree. However leave the small ones intact. This should provide enough clearance for one year because the branch will often spring upward after removing branches from the tips.
If necessary we would remove all branches back to the trunk one or more years later.
What if the lower branches are large in diameter?
Raising the tree canopy with large diameter low branches can initiate trunk decay if these large branches are removed. In order to prevent this we would recommend thinning them reducing their length with drop crotch cuts instead of removing them completely.
This will slow their growth rate, and eventually the trunk will grow to become larger than the branch. This gives the tree an opportunity to form the branch defense zone at the base of the branch thus minimizing trunk decay once it is removed. When raising the canopy it may be necessary to attend to any structural pruning that needs to be done to correct defects. It is inappropriate to simply remove lower branches without correcting structural problems.