What constitutes a dangerous or hazardous tree ?
A dangerous tree is one which is in such a poor condition that it may be about to collapse either in part or whole. A dangerous tree may or may not be hazardous depending upon where it grows. A tree in a privately owned field is less potentially hazardous than one in a public park, for example.
How does a dangerous tree differ from a defective tree ?
Most trees have defects, but the vast majority do not render a tree dangerous. Defects may include minor dead wood where squirrels have stripped bark or minor decay pockets where bark has been damaged and the tree has suffered bacterial or fungal infection. It is the type and extent of the defect that is important in determining whether or not a tree is dangerous.
What are the symptoms which can make a tree potentially dangerous/hazardous ?
There are a number of defects which, depending upon their extent, may be regarded as potentially hazardous.
Is a tall tree dangerous ?
No. A tree will grow (within its species limits) as large as the space, light, water, nutrition and oxygen available to it permits. Trees cannot grow too tall – except in human perception.
Is a leaning tree dangerous ?
Not necessarily. One of the reasons a tree grows with a lean is because it is in close competition with another specimen and has been forced to grow at an angle to chase the light. In response the tree lays down denser wood on one side of its trunk. There may be a problem however if a previously vertical tree suddenly develops a lean.
Is a hollow tree dangerous ?
Certainly some hollow trees may have so little healthy tissue surrounding the hollow area that they must be regarded as dangerous, but this is by no means the norm. Trees do not become hollow overnight – it can take decades – and while the centre of the tree (the heartwood) may be decaying, the tree continues to lay down healthy wood (sapwood) around the outside of its trunk. This results in the formation of a cylinder, the strength of which depends upon the percentage of healthy to unhealthy tissue.
Do I need Council permission to cut down a dangerous tree ?
In law you do not need the permission of the Local Planning Authority to cut down a tree which is dead, dying or dangerous. However anyone proposing to cut down a tree because of these reasons is strongly advised to give the Local Planning Authority five days notice before carrying out the work, except in an absolute emergency. If work is carried out to a protected tree because of these reasons, the owner or agent must be able to prove that the tree was dead, dying or dangerous and, if it came to a prosecution case, to prove this in court. This can be using photographs, keeping sections of decayed wood and any other relevant evidence.
