Explaining Arboricultural Terms
Here we define in more detail some basic Arboricultural terms used to help you describe your tree needs. Of course if you would like further explanation and advice, please send us an email or give us a call.
What is Crown Lifting?
Definition: Raising the canopy of the tree.
Crown Lifting is the selective pruning and removal of lower branches to increase the distance between the ground level (or feature) and the lower crown. This process is normally carried out where there is a need to clear footpaths, roads, gardens, buildings, signs and also allows for increased light to first storey windows.
UK common practice clearance for vehicles on highways is 5.2 metres (17ft) and for pedestrians on footpaths is 2.5 metres (8ft). This type of pruning should ideally be completed before a tree reaches maturity to avoid creating large wounds and when done correctly does much less damage to a tree than reducing the canopy size to improve light infiltration to a property.
What is Crown Reduction?
Definition: Reduction of the height and/or spread of the tree through recognised pruning practices.
Crown reduction is used to reduce the height and/or spread of the crown of a tree by the removal of the ends of branches to suitable secondary growing points whilst maintaining the tree’s natural shape as far as practicable.
The objective is to make cuts so that the foliage is left intact on the outer edge of the new, smaller canopy, with pruning cuts not evident when you stand back from the tree after pruning. Topping and lopping are not appropriate techniques for reducing the size of the tree because they significantly reduce the tree’s potential energy and may result in more costly cyclic management needs.
It requires substantial talent and experience to perform this operation; of course this is a temporary measure because the tree will quickly revert to its natural size. Crown reduction is usually quoted as a measured height or width (in metres) to be retained along with a maximum wound size and number of branches to be removed. In many instances, canopies cannot be properly reduced in size to the extent desired and certain species such as beech do not respond well to crown reduction.
It is very difficult to use crown reduction to permanently maintain a tree at a smaller size without causing the tree to decline. Consider pollarding from a young age to maintain the height of a tree in close proximity to structures. However tree removal and replacement with a smaller, more suitable and maturing plant, may be the choice that minimises the input of resources.
When a customer wishes to reduce the height of a tree, crown reducing is much preferred to topping. Crown reduction should not be used to reduce the chances of a structurally sound tree blowing over in a storm.
What is Crown Thinning?
Definition: Removes mostly secondary branches (small branches) from throughout the crown without reducing the extent of it.
Thinning is may be used to reduce limb weight on mature trees in order to compensate for structural defects such as cracks, hollows, and cavities, although this should only be undertaken occasionally with the advice of an experienced Arboriculturist. On occasions the severity of some diseases and pest infestations can be reduced by crown thinning because more light and air can move through a thinned canopy, this keeps the foliage drier, which may discourage diseases. Thinning can also emphasize the beauty of the trunk and main branches and increase light penetration to the ground, which can enhance plant growth under the tree to a limited degree.
Proper thinning will not change the overall size of the tree, it will remain the same height and width as it was before thinning. Correct thinning is done on relatively small branches in the leafy area of the canopy towards the ends of the main branches, whereas structural pruning is done on larger branches lower on the tree towards the trunk or anywhere it is needed.
Some species of tree are not suitable for crown thinning as regrowth can be excessive and so causing a more dense crown e.g. lime.
What is Pollarding?
Definition: Maintaining/reducing a tree to a specified height from a young age.
A frequently misunderstood term, and used in two different contexts. Traditionally and still commonly used this term describes the removal of most branches on a trunk and stems. Mature trees that have not been pollarded before are generally not suitable candidates for this type of pruning due to the large wounds that such treatment produces which may jeopardise the long term future of the tree (topping and lopping). A more frequently used definition can mean the regular (annual or biannual) pruning back of small branches to the same point resulting in the formation of a ‘pollard head’. Pollarded trees usually require regular treatment of re-growth.
A useful method to control the size of a tree that has been planted too close to structures such as buildings, street lighting or electric wires.
Once begun it is essential that pollarding continues. Preferably, the pollarding process should begin when a tree is very young.
It should be noted that different species of tree respond to pollarding in different ways and pollarding may not be suitable e.g. willow trees respond well but birch do not.
Tree Felling/Sectional Dismantle
Definition: The removal of a tree/s to leave a stump.
It is sometimes necessary to remove a tree if it is dead, damaged, or simply not felt suitable for the location. This can be removed as one piece or many, depending of the site location/layout.
At Castle Tree Care Ltd we are leading Lincolnshire Tree Services in large tree removal using cranes and rigging equipment and, have many years’ experience in removing dangerous trees. When removing large dangerous trees in close proximity to valuable features such as a house we will often use a crane or ropes to ensure their safe removal and the safety of our staff.
Tree surgeons can work at height using a rope and harness however, under the hierarchy of the Work at Height Regulations 2005, we at Castle Tree Care Ltd endeavour to work using our own MEWP, more commonly known as a Cherry Picker.