There are plenty of reasons why neighbors have disputes, but one of the most common comes from the proximity of trees to their properties. The issues caused by trees vary from blocking one neighbor's view to putting the other's home at risk.
What should you do if you think that your neighbor's tree is causing a problem? It's easy; talk to them. If they agree to trim the tree back or remove it, then you don't have a problem. If not, then you have some legal options.
If you can show that the tree is dangerous because of rotting or that it blocks your view in a scenic area, you may have a case to take your neighbor to court. Usually, mediation or arbitration works well if you and your neighbor are willing to negotiate with the help of a third party. If not, you can take your neighbor to court and allow a judge to hear the case. The judge then makes a decision on what should happen to the tree.
Keep in mind that if a tree is on your neighbor's property and isn't in violation of any local ordinances, there may not be much you can do. If that tree is blown over during a storm but was in good health beforehand, it may simply be considered an act of nature and not something your neighbor would be liable for. Additionally, things like leaves, seeds and acorns are naturally occurring objects, and it's not the tree owner's responsibility to remove them from another party's property. On the other hand, if your neighbor's tree is crossing onto your property, you retain the right to cut roots or branches that are affecting your property.
Source: FindLaw, "Neighbor Disputes: Trees," accessed Nov. 08, 2017