Tree surgery terms

Crown The crown of a tree is the whole of the above ground part of the tree with the exception of its main trunk
Crown thinning Removal of a proportion of secondary branches within the trees crown so as to reduce branch density within the crown. This will often include removal of crossing, weak, dead or damaged branches within the crown, e.g. Birch, crown thin by 10%
Crown raising/lifting Removal of lower branches or parts of branches of the tree to a specific height above existing ground level (e.g. 4 metres), so as to provide increased head clearance beneath the tree, e.g. Willow, crown raise to 4 metres
Crown reduction A reduction of the overall size or circumference of a trees crown by generally reducing the overall length of its branches but without destroying the basic shape of the crown, e.g. Oak, crown reduce by 20%
Dead wooding Removal of dead and damaged branches back to sound wood
 Pollarding A cutting back of all branches of a tree leaving only its trunk or cutting back branches to a lower point for the formation of a new head