My question involves real estate located in the State of: NJ

I just bought the house last month. At the back corner of the yard there are 4 Pine trees that are 60 to 80% on my neighbor's property and 20-40% on mine. Who's trees are they?

I'm having an arborist come to look at a bunch of trees I have, and I will have him look at these as well. They do not look like they've been maintained at all, they're an eyesore and they shade my roof in the AM and I want to put in solar panels. Needless to say I'd like them removed, I will pay for it, that's not the issue. I'm just curious as to the legality of me cutting them down, do I need the neighbor's permission, or can I just do it since they are on both sides of the line?