I fully qualified at Merrist Wood in 2004. Arguably the best training courses for tree surgeons in the world. Since then I have done a number of jobs around the local area.
There are a number of reasons why you might require a tree to be removed; it may be deceased, it could be decaying making it unsafe or it could just be in the wrong location. Whatever the reason, I am qualified to remove it either by straight felling where it is completely safe to do so or by bringing the tree down in smaller sections on ropes.
Crown reduction is used to reduce the height and/or spread of the crown of a tree by the removal of the ends of branches whilst maintaining the tree's natural shape as far as practicable. All cuts should be made after a bud or branch.
Crown thinning is the removal of a small portion of secondary and small live branches to produce a uniform density of foliage around an evenly spaced branch structure. It is usually confined to broad-leaves species. Crown thinning includes crown cleaning and does not alter the overall size or shape of the tree. Common reasons for crown thinning are to allow more light and air penetration to the inside of the tree's crown or to the landscape below, reduce wind resistance or to lessen the weight of heavy branches. Routine thinning does not necessarily improve the health of a tree. Trees produce a dense crown of leaves to manufacture the sugar used as energy for growth and development. Removal of foliage through pruning can reduce growth and stored energy reserves. Heavy pruning can put significant stress on a tree. You should not reduce the crown by more than a maximum of 30% as this could seriously weaken the tree. If it is a large tree you could be better off reducing it over several years.
Crown lifting is done by removing the lower branches. In the pictures here I raised the crown on some yew trees as the owner was worried about the horses eating it. Yew is very poisonous.
The removal or dead, dying, diseased, broken, crowded, crossing, rubbing, weakly attached and low-vigour branches as well as climbing plants (e.g. ivy). Most routine pruning to remove weak, diseased, or dead limbs can be accomplished at any time during the year with little effect on the tree. As a rule, growth is maximized and wound closure is fastest if pruning takes place before the spring growth flush. Some trees, such as maples and birches, tend to 'bleed' if pruned early in the spring. It may be unsightly, but it is of little consequence to the tree.
Some trees are protected by TPOs. These trees are often highly visible to the public, and integral to the local environment. Before any work can be done on trees you should check with your local council first to make sure the tree/s in question are not listed with a TPO. Should you wish to work on - or remove - a protected tree, you will need to seek permission from your local council.
If the tree constitutes an immediate risk, you can take steps to make the tree safe prior to receiving permission - but the onus is on you to prove that the work was absolutely necessary.
If you identify a dangerous tree owned by somebody other than yourself, express your concern to them and encourage them to take action. If the tree is deemed 'imminently dangerous', the council can require the owner to act by law.