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In order for our prospective/existing clients to be fully aware of the definitions of work specifications outlined in British Standard 3998:1989 'recommendations for tree work', we've included them below for your reference.

Crown Reduction

The reduction of the complete outline dimension of the canopy, from the tips of the branches to suitable internal branches. The diameter of the remaining branch should not be less than one third of that removed. After a crown reduction the tree should retain an overall appearance typical for the species or variety of the tree concerned.

Basic example:


Crown Thinning

The removal of a proportion of the small, live woody growth to reduce the density of the foliage throughout the canopy. This operation is usually specified as a percentage. The aim is to produce an evenly distributed canopy of foliage on a well-structured, balanced and sound skeleton of limbs and branches, typical for the species or variety of tree concerned.


Crown Lifting

To increase the distance between the ground and the lower branches of the crown of a tree by removing parts of branches or whole branches. This is common practice where trees overhang roads or footpaths.



Defined as the cutting back of all branches of a tree back to the main stem at a specified height above the ground. The result is a production of a quantity of vigorous shoots usually from close to the cuts, but in some species (e.g. Lime) the shoots may be throughout the length of the trunk. Where pollarding has taken place previously the new pollard should generally be just above the previous pollard points, unless decay is considered so extensive that re-growth shoots would be potentially dangerous.


Section felling/Dismantling

Dismantling is the method by which a tree is brought down by a climber in sections, often by using lowering and rigging rope systems. It is necessary for a tree to be considered for removal for various reasons: 

  • The tree is diseased and puts other trees in the surrounding environment at risk of becoming infected.
  • Health and Safety - if the tree is in a state of decay, has been irreparably storm damaged or is potentially of considerable risk to either public or private safety.
  • If the tree is in an area affected by planning applications or construction projects. 
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