Introduction:
Professional tree surgeons use a range of terms and phrases to carry out various tree works, which can often be a little confusing for clients. Here are our tree surgery definitions of some of the more common ones used.
Crown Thinning –
This method is used by removing smaller internal branches that are potentially rubbing or crossing, causing self-wounding and to allow more light and air to penetrate the canopy of the tree. It’s also used to improve the tree’s overall health. For fruit trees it can help produce better fruit crop, and it lessens wind loading (wind sail) while trees are in full leaf which can help to reduce limb failure / branch snap out. Care is needed however, as too much thinning could cause a Lion’s tail effect which creates level arm stress on unions (branch junctions) leading to potential failure. Over thinning can also cause blisters/sun burn on thin barked trees such as beech.
Crown Lifting –
Is the removal of the lower branches or secondary sub lateral branches of the canopy, although removing large branches growing directly from the trunk is not recommended as large wounds can be an entry point for disease and pathogens, which can be detrimental to the overall and long-term health of the tree. This is an effective method for allowing more light through to understory planting without reducing the whole canopy of the tree.
Crown Reduction –
This is done by removing the ends of the branches which form the canopy of the tree to reduce the height and overall spread of the canopy. It is usually recommended to lessen the chance of mechanical stress on the whole tree, or individual branches. It’s also recommended for trees in built up/urban areas where a smaller size is needed to be maintained, however not all species are suited to this, and your tree professional will be able to advise you.
Pollarding –
is to remove the top of the tree to encourage new growth or manage the size of an urban tree. This will usually fall into a regular and cyclical pruning plan as lapsed pollards can be prone to limb failure due to weak or decayed attachment points.
Coppicing –
This is cutting a tree to a low stump to allow it to regenerate from ground level, typically used in charcoal/fuel production (hazel trees, ash, willow). It is sustainable and used for biomass. We also find this practise when us a large shrub or tree has become too large for its location.