Crown Thinning

Crown thinning is the removal of a portion of smaller branches, usually at the outer crown, to produce a uniform volume of foliage around an evenly spaced branch framework. It is usually confined to broad-leaved species. Crown thinning does not alter the overall size or shape of the tree.

Crown Lifting 

Crown lifting is the removal of the lowest branches and the work on lower branches to allow for future removal. Good practice says that crown lifting should not usually include the removal of large branches growing directly from the trunk as this can cause large wounds. 

Crown Reduction

The reduction in height and or width of the crown (the foliage producing part) of a trees. Crown reduction may be used to reduce mechanical stress on individual branches or the whole tree. It can be used to make the tree more appropriate to its surroundings or to reduce the effects of shading and light loss, etc. The final result should retain the main structure of the crown, and retain a significant proportion of the leaf bearing structure, and leave a similar, but reduced outline.

Coppicing

The cutting down of a tree within 300mm (12in) of the ground levell on a regular basis, usually applied to certain types such as Hazel and Sweet Chestnut to provide stakes etc.

Pollard

The  removal of the top of a young tree at a prescribed height to encourage multistem brancing from that point, often seen in urban enviroments. Once started, it should be repeated on a regular basis always retaining the initial pollard point.

Lopping and Topping

Generally regarded as incorrect terminology but still used by local councils as part of Planning legislation. Lopping refers to the removal of large side branches  and topping refers to the removal of large portions of the crown of the tree . Often used to describe crude, unskilled pruning.

Root pruning

The pruning back of roots . This can affect the stability of the  tree and should be carried out with the overall stability of the tree in mind.

Stump Grinding

The mechanical removal of a tree stump  using a grinding machine.