To prune a tree without putting the tree at risk from tree diseases through bad pruning, there are certain ways that have to be learnt in the trade. The methods an Arborist uses to prune a tree are called Natural Target Pruning. On a tree's branch, you will find a branch collar and branch bark ridge. The branch collar should not be cut into because that will spread decay into the tree. The same goes for the branch bark ridge.
Crown lifting is the selective removal of the lower branches of a trees crown to increase the distance between the base of the branches and ground level. This allows more light through and canprevent obstruction.
When a tree is section felled by an Arborist, it is taken down in a controlled manner. There can be any number of reasons why a tree is section felled, usually it is because there is a building nearby or underneath the tree.
Crown thinning is the selective removal of branches evenly throughout the tree to reduce the density of the tree.However, it does not change the overall size or shape of the tree This technique can be used to create more light and air throughout the tree. Crown thinning opens the foliage of a tree, reduces weight on heavy limbs, and helps retain the tree's natural shape.The end result should be a tree looking more open and filtering light through.