Tree Surgery Terminology and What Each Term Means?

The most common course of action when you notice that your trees or shrubs need additional care is to get in touch with a licensed tree surgeon. Normally, before you receive your quote, the tree surgeon will come over in-person to see what needs to be done. He will first listen to all of your requirements and questions and then inspect the tree/trees himself to see if they really require any pruning.

Now, If action is indeed required, the arborist may use some unfamiliar (to you) tree surgery terminology, which describes the work that will need to be done. Although some of these terms might sound familiar, they may actually mean something completely different. 

So let’s look at what the different tree surgery terms mean and when they’re most often used. A very common term that you will be seeing a lot in this post is the word “crown”. This word refers to the framework of the tree which consists of different types of branches and shoots, as well as the foliage.

Main Tree Pruning Terminology

There are three main tree pruning terms that get thrown left and right quite often.

Crown Thinning

This term refers to the removal of smaller branches, usually located at the outer crown of the tree. Pruning these promotes dense foliage around the evenly spaced branch structure. Crown thinning is mainly used on broad-leaved species of trees. It’s a method that does not in any way alter the main body of the tree, in terms of size or shape. Crown thinning allows more sunlight to pass through the tree’s branches and improves the airflow.

Crown Reduction

Crown reduction refers to the reduction of the tree crown’s height and spread. The cuts used in crown reduction should be as small as possible and not go over 100 mm in diameter. This method is used for reducing the mechanical stress on certain branches or even the whole tree, in some cases. It’s also useful for reducing the effects of light loss and shading. After the crown reduction, the tree’s crown should retain its main framework with the only difference being the smaller yet similar outline (which can in cases be non-symmetrical).

Crown Lifting / Crown Raising

Crown raising is the practice of removing or preparing to remove the lowest branches of a tree’s crown. This method is extremely effective at increasing the light transmission to areas close to the tree, while also enabling access under the crown. Crown lifting does not include the removal of the larger branches which grow directly from the tree’s trunk since cutting these can wound the tree and even cause decay. This can lead to many long-term problems for your tree in the future. Crown raising should also be avoided on older more mature trees or if necessary, it should be restricted to the shortening of their primary and secondary branches rather than their whole removal.

Other useful terms associated with tree surgery and arboricultural work

Aside from the main crown-related terminology, there’s also additional tree surgery lingo you can hear your tree surgeon mention. Below, we’ve provided a pretty comprehensive list of what each term means.


  • Adaptive growth - The growth of new branches on a tree caused by a stress concentration in its structure.
  • Adventitious/epicormic growth - This refers to the growth that arises from new or dormant buds directly from the tree’s main branches or trunks.
  • Arboriculture - A landscaping term used to describe the practice and study of caring for trees. 
  • Arborist - A term used to describe a professional, who deals with arboriculture. Although similar to tree surgeons, arborists are a bit different. They don’t really prune, trim and fell trees, but they identify diseases in trees and provide recommendations for the appropriate treatment. 
  • Arisings - The debris left behind after a tree surgery job - branches, twigs, logs, foliage, leaves and wood chips.


  • Branchwood/Brash/Brushwood - These terms all refer to the branches and foliage removed from a tree.
  • BS3998 - British Standard Recommendations for Tree Work.
  • BS5837 - British Standard Recommendations for Trees in Relation to Construction.
  • Buttress Roots- The roots located at the base of the trunk.


  • Cable Bracing - The use of professional hardware or synthetic rope on a tree to provide additional support for its weaker branches.
  • Callus - This refers to soft tissue that forms over a cut or wounded tree surface, in order to regenerate it.
  • Cavity - A hole located within the tree’s body, cavities are usually associated with decay and deterioration.
  • Co-dominant stems - Refers to two or more main stems, which are around the same diameter and grow out of the same location on the tree’s main trunk. Usually, as the tree grows older and bigger, both these stems remain similar in size without any of them becoming the dominant one.
  • Coppicing - Cutting down the main growth of a tree down to a stump, no bigger than 12 inches (300mm) off the ground. This method is used, in order for the tree to regenerate and start anew. However, it works only on selected and appropriately aged species of trees - Hazel, Sweet Chestnut, etc.
  • Cordwood - Timber no bigger than six inches (150 mm) in diameter and smaller than 12 inches (300 mm).
  • Coronet Cut - A cut that resembles a natural fracture, it’s used to mimic the jagged edges of a broken branch following a storm. This cutting technique is mainly used on wildlife sites.


  • Deadwood - Dead branches or stems caused by natural ageing or other external influences.
  • Decline - Refers to signs that point to a tree’s lack of vitality. These signs can be anything from reduced leaf size to reduced colour and density.
  • Dieback - A tree condition during which the tips of its branches die out.
  • Dormant - The inactive phase of trees and other plants, which usually occurs during the colder months of the year. During this period, trees stop producing growth and their leaves begin to shed (unless they’re evergreens).
  • Drop Crotching - A type of thinning in which the tree’s size is reduced in a way that preserves its natural shape.


  • Felling - A tree pruning technique used to remove the entire tree by cutting it at the base and then directing it to fall in a desired spot.
  • Fertilising - The application of tree stimulating substances that promote tree growth and stunt decline.
  • Formative pruning - The act of pruning young trees, in order for them to take a desired form or shape. This method helps prevent the tree from suffering from major physical weaknesses once it matures.
  • Fruiting bodies - Fungal structures which contain spores. These can colonise both the living and dead tissues of a tree or its roots.


  • Habit - The shape of a tree.
  • Hazard beam - A potentially problematic large branch.
  • Height reduction - The reduction of a tree from its top, down to its lower branches.


  • Included bark - Bark tissues that have developed as a result of two or more stems that have grown closely together and have created weak under-supported branch angles.


  • Leader - A tree’s main upright stem or shoot, which emerges from the centre of the tree.
  • Lion Tailing - An improper and damaging pruning technique that is used to remove an excessive number of inner lateral branches from a tree. Although this method makes your tree more aesthetically pleasing to look at, it can damage it severely, therefore, it’s not recommended.
  • Lopping and topping - Lopping is the removal of large side branches through vertical cuts, while topping is the removal of a big chunk of a tree’s crown through horizontal cuts. Both are inappropriate pruning techniques.


  • Mobile Elevated Work Platform (MEWP) - A machine used for accessing a tree when it’s not suitable or unsafe for climbing.


  • Painting or sealing - The covering of cuts or wounds on a tree with bitumen-based paint. This is an outdated healing method that has been proven to do more harm than good.
  • Pollarding - The practice of regularly cutting back a tree’s crown down to bare branches. It’s used to maintain the shape and height of a tree while it’s young. And remember, this is only suitable for certain species of trees.


  • Retrenchment pruning - A type of pruning that helps encourage the development of the tree’s lower shoots. This method is also effective at emulating the natural process of tree ageing.
  • Ringwood/ Rounds - As the name suggests, this refers to small disk-shaped pieces of wood which are sometimes left behind after a tree surgery job.
  • Root pruning - The process of pruning a tree back of a trees’ roots.


  • Sail area - The part of the tree which is most affected by wind.
  • Scaffold branches - A tree crown’s main structural branches.
  • Section felled - Free fall - A felling method in which the tree is cut down in sections each of which fall down free to the ground.
  • Section felled - Rigged - A felling method used when there are things below the tree that need protecting. The tree is cut in sections, each of which is rigged so that it doesn’t damage anything located beneath the tree.
  • Selective reduction - The reduction of branches that are located outside the uniformity of the tree’s crown.
  • Stump grinding - The complete removal of a tree’s stump through the use of a specialized machine.
  • Sucker - A shoot that emerges from the roots.


  • Thinning - The process of removing small branches from the crown of a tree.


  • Veteran tree - A protected tree that is very old and of great size, and holds important cultural or nature conservation value.
  • Vitality - The degree of life functions within a tree.


  • Whorl - A pack of branches which arise from the same level on a stem.
  • Windthrow / Windblown - A tree that has fallen due to strong winds.

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