Branches are often removed because they either damaged or dead. Branches can die off for a number of reasons including light deficiency, storm, pest or disease damage.
Over time the dead branch will decay back to the parent stem and fall off. However, deadwood is often dry and brittle and cannot bend in the wind like a living tree or branch – this makes them unpredictable as there is the possibility that they can break and fall at any time. In particular, a dead branch or treetop that is already broken off – often called a “hanger” or “widow maker” – is especially dangerous.
It is important to have dead wood removed from a tree as soon as possible, in order to avoid causing injury or damage to property. Situations that usually demand such removal would normally be trees that overhang public roads, houses, public areas and gardens.
In addition to the obvious safety concerns, another reason to deadwood a tree is to improve the over all look of the tree. Not only will the tree look healthier, it also reduces weight and wind resistance and can help overall balance.