in short...

It is a property owner’s responsibility to ensure his/her trees are in safe condition. Assessments should be done by qualified arboricultural consultants.

the full answer...

It is a property owner’s responsibility to ensure the trees on his or her property are in a safe condition. Assessment of the diseases or defects affecting a tree is essential and should be done by qualified arboricultural consultants. Once a tree has been recognised as being dangerous, they can supply a written report recommending the necessary work and care for the tree. It is worth noting that insurance companies are increasingly refusing to pay out for damage caused by trees that have not had a recent survey. Policies should be checked to ascertain the exact requirements of the particular company.

Some common problems which indicate the possibility of unsafe trees are cavities or decayed wood along the trunk or in major branches, fungus present at the base of the tree which reveal diseases, such as honey fungus, could be present in the tree.

Cracks in the trunk could weaken the tree and splits at the union where branches attach can cause them to drop without warning. If adjacent or nearby trees have fallen or are dead there may be a common cause which will subsequently affect healthy trees nearby. Other causes for concern are if the trunk of a tree develops a strong lean or visible roots are broken off, injured or damaged, if there has been recent construction in the area or if tree branches are interfering with power lines overhead.

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