When it comes to falling trees, the blame can be a bit different for each situation.
Fallen trees are one of the top neighbor disputes, so make sure to have good communication with your neighbor if caught in this situation.
Say that you had a horrible wind storm that knocked your tree over into the neighbors roof.
Technically that is considered an act of god, and you would not be held responsible even though it is your tree.
The house that was damaged by the tree, should be covered by that persons homeowners insurance.
In that situation no one is to blame for fault, because it was an act of god.
But in some situations minor details can change who receives blame.
For example, if the tree were to fall on the house while the owner was trimming branches, that would likely become the owner of the trees fault.
Also if the owner of the tree showed negligence when maintaining the tree properly, they could be at fault.
It is hard to prove anything after the tree has fallen, so in most cases the victims homeowners insurance will cover repair costs.
A tree falling and damaging someone's property can ruin a good relationship between neighbors.
If all conditions are ideal, and it really was an act of god, then it was not the owners fault and the insurance from the damaged house should cover costs.
To keep a good relationship with your neighbor it may be a good idea to offer a little money to help cover the costs of repair, or the costs of the deductible.