At A Binns and Company we know that some of the "jargon" used by tree surgeons can be confusing. We also know the impact that any work to the trees on your property can have as a whole and that this can make choosing a tree surgeon especially daunting. We hope that this list of services and terms will help to dispel any confusion and give you a better understanding of any work that is to be undertaken.

Main Tree Pruning Definitions


Crown thinning is the removal of a small portion of secondary and small live branches from the tree to produce a uniform density of foliage around an evenly spaced branch structure. It is usually confined to broad-leaved species. Crown thinning includes crown cleaning and does not alter the overall size or shape of the tree. Common reasons for crown thinning are to allow more light to pass through the tree, reduce wind resistance or to lessen the weight of heavy branches.
Scroll your mouse over the diagram to the left to compare the tree before and after a crown thin.


Crown lifting is removal of the lowest branches of a tree and preparing of lower branches for future removal. Good practice dictates crown lifting should not normally include the removal of large branches growing directly from the trunk as this causes large wounds which may jeopardise the long term future of the tree. Common reasons for crown lifting are to bring more light and give access for traffic. In the UK common practice dictates clearance for vehicles is 5.2 metres (~17 feet), and for pedestrians 2.5 metres (~8 feet).
Scroll your mouse over the diagram to the right to compare the tree before and after a crown lift.


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 whilst maintaining the trees natural shape as far as practicable.
Scroll your mouse over the diagram to the left to compare the tree before and after a crown reduction.

Crown Clean
Similar to Crown Thin but crown cleaning involves the removal of dead, dying, diseased, broken, crowded, weakly attached and low vigour branches as well as climbing plants (eg. Ivy).

Other Words and Terms Assocaited with Tree Care

Bracing
Bracing is the term used to describe the strengthening or supporting of a tree by means of cables, rods, webbing or similar.


Branch Bark ridge and collar
More noticeable on some species than others the branch bark ridges appear like "creases" that form along the top side of a branch where it meets the trunk. Also more noticeable on some species than others is the branch collar, a swelling at the base of the branch. Neither the branch bark ridge nor collar should be cut. See the blog article on When and How to Prune Your Garden Trees.

Callus
Scar tissue laid down by the tree in order to cover and protect a wound, eg. a pruning wound.

Cavity Work
Removal of material from cavities and drainage of cavities achieved by drilling through living wood. Modern research indicates this should not normally be carried out.

Co-Dominant Stems
See "Forked Growth"

Conservation Area
The designation given to an area by a Local Planning Authority (LPA) which requires, amongst other things, six weeks advance notice to be given to the LPA prior to certain tree works. In other words, most works to most trees within a Conservation Area must not be undertaken without notifying the LPA in writing six weeks in advance. Failure to do so may be a criminal offence.

Coppicing
The cutting down of a tree with within 300 millimetres (12 inches) of the ground at regular intervals (typically on a one to five year rotation). Traditionally applied to certain species such as Hazel and Sweet Chestnut to provide stakes etc.

Crown
The section of the tree formed by its branches and usually starting above the stem.

Dead, Dying, Dangerous or a Nusance
The catch-all phrase describing the conditions of trees to which protection afforded by Tree Preservation Orders or Conservation Areas does not apply. Legal definitions are the subject of much debate, often through the courts, and professional advice is strongly recommended.

Decline
When a tree exhibits signs of a lack of vigour and progressing toward its death.

Dieback
Tips of branches exhibit no signs of life. As decline progresses so more branches are affected and to a greater extent.

Dormant
The inactive condition of a tree, usually during the coldest months of the year, when there is little or no growth and leaves of deciduous trees have been shed.

Drop Crotching
Shortening branches by pruning off the end back to a lateral branch which is at least 1/3 of the diameter of the removed branch.

Fertilising
The application of a substance usually to the tree's rooting area (and occasionally to the tree) to promote tree growth or reverse or reduce decline.

Flush Cut
The removal of a branch by cutting very close to the branch to be retained, cutting through the branch bark ridge and/or collar, thereby reducing the ability of the tree to callus.

Forked Growth (Co-dominant stems)
The development of two or more leading shoots of roughly equal size and vigour competing with each other for dominance.

Formative Pruning
Pruning during the early years of a tree's growth to establish the desired form and/or correct defects or weaknesses.

Fungi Fruiting Bodies
Any spore bearing structure on a stalk (like a toadstool) or attached directly to the tree (a "bracket" fungus). Note: some are harmful (cause disease - pathogenic), some are harmless (living on material already dead - saprophytic) and some are beneficial (symbiotic).

Lopping and Topping
Generally regarded as outdated terminology but still part of planning legislation. Lopping refers to the removal of large side branches (the making of vertical cuts) and topping refers to the removal of the head or crown of the tree (the making of horizontal cuts). Often used to describe crude, heavy-handed or inappropriate pruning and not generally considered good practice.

Pathogenic
Disease inducing - usually referring to fungal fruiting bodies.

Pollard
A frequently misunderstood term, and used in two different contexts. Traditionally and still commonly used this term describes the removal of all branches from the trunk. Mature trees that have not been pollarded before are generally not suitable candidates for pollarding due to the large wounds that such treatment produces which may jeopardise the long term future of the tree. A less 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 regrowth.

Root Pruning
The pruning back of roots (similar to the pruning back of branches). This has the ability to affect tree stability so it is advisable to seek professional advice prior to attempting root pruning.

Topping
See "Lopping and Topping"

Silvercultural Thinning
The removal of trees to promote the better trees in the group

Tree Preservation Order (TPO)
Statutory protection applied to a tree or trees meaning that most works to most trees covered by a TPO must not be undertaken without the prior written consent of the LPA. Failure to do so may be a criminal offence.