Don't be so sure....private land or not - I have 5 acres and a very LARGE old oak tree in the back of it. Its leaning over into my neighbors acreage and I was afraid it might take the fencing out in a big storm so I wanted to cut it down. Mentioned it to the same neighbor and he called the county on me. Apparently in our county you have to get PERMISSION TO CUT the larger Oaks EVEN ON YOUR OWN property! I couldn't believe it!
Be careful with trees on property lines. Notify your insurance agent and send a certified letter to your neighbor that you feel an overhanging tree could cause some damage in the event of a natural disaster. If the neighbor objects to your removing it then he assumes any responsibility for damage to his property. Same thing with root systems. In Eureka the redwood roots from a adjoining property crept under the foundation of a neighbors house and lifted the foundation over a period of 10 years. Caused $100,000 in damage. If you cut the roots and the tree falls onto an adjoining property you are at fault unless you received permission from the trees owner to sever the root system..