Heartwood Tree Surgeons Limited believes that our customers should be fully aware of the definitions of work specifications outlined in British Standard 3998:1989 Recommendations for tree work. These are standards that we are proud to work to and we have listed 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.
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, providing the wounds left do not exceed 50mm. This is common practice where trees overhang roads or footpaths.
Crown Cleaning
The removal of weak, diseased and dead branches or limbs throughout the crown of the tree as necessary to prevent them being a nuisance or causing damage if they were to shed.>
Pollarding
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.
All of the above descriptions on this page are taken from. "BS 3998:1989 Recommendations for tree work"
