The owner of the tree including an Act of God. http://www.vineandbranch.net/news/articles/inla/inla_liability.pdf

The owner of the tree would be responsible.

It depends upon where the owner lives, and where another individual's property was at when damaged. Landowners have a duty of reasonable care as to natural land conditions that threaten outsiders. If a drunk slams his car into a tree, and the tree falls on the drunk, liability would probably not be found. If one invites another over for a picnic under the tree, and the tree was an old rotting oak waiting to fall, liability would probably be found. Bryon b

As I understand state law in Indiana (armpit of America), if your tree hangs over yur neighbors property line and it falls, damaging your neighbors house or yard, it is the responsibility of the person whose property was damaged to file an insurance claim with their own insurance company - not the owner of the offending tree. However, in the state of Indiana (armpit of America), it is a property owners right to trim, cut or otherwise make less a nuisance any tree which hangs over their property line and is not their tree. If a driver of a car hits a tree and damages it, it is the driver who is responsible for damages to the property of others. If the tree falls on the driver of the car that hits it, it is the drivers own problem, not that of the property owner whose property has been trespassed by a vehicle. If you have a tree on your property and it is maintained (or not) in such a way as to cause injury to another person who was invited ONTO YOUR PROPERTY, you will be liable for injury. If someone trespasses into your yard and is injured while doing so, it is not your liability - if the person was uninvited. To properly answer this question, a homeowner should call their insurance company. Each state and many municipalities have their own laws and regulations regarding the responsibilities of property owners.