Crown raising or lifting
Crown lifting is the removal of the lower branches of a tree crown to achieve a specified height clearance from ground level. Ideally the amount of the crown raise should not exceed one third of the tree’s crown.
Reasons for crown lifting may include:
- Headroom clearance for vehicles and pedestrians, The Highways Act 1980
- Utilities (power and phone lines)
- Building clearance to either improve views, allow light into a building
- Reduce risk of damage to a building through contact with the tree.
- To allow light under the canopy for competing plants
Tree crown reductions are the most common form of pruning. This may involve rebalancing the crown or reducing the height and or width of the crown to improve the aesthetics or life span of a tree. Another reason for crown reduction to be carried out may be to reduce the likelihood of storm damage occurring.
Crown thinning is the removal of a percentage of the trees crown without altering the size or shape of the crown. Commonly the operation is carried out on broadleaved species to allow more air and light though a tree’s crown. This technique also reduces wind sail in the tree, therefore reducing the likelihood of storm damage.
This is a severe tree pruning technique used on some species of trees that need to be managed in relation to their environment, or if there is substantial instability in a tree. Pollarding can cause rapid regrowth and is a technique that may need to be carried out on a yearly/two yearly basis.