I did a little research on permits, but I'm not sure if you will need one or not. If you do need one, they're $25, and you'll need to show proof of liability insurance. Here's a link to some info: http://www.dec.ny.gov/regulations/51387.html Here's another possible option for you - a member here was looking for help cleaning up a property which may be very close to where you live, and it sounds like there's a lot more of that black locust (which is primo firewood) like you have in your first 2 pics: http://firewoodhoardersclub.com/forums/threads/who-wants-free-b-l-rounds.7460/
Esla, I'm impressed. If you are strong enough to handle that Husqvarna safely, then you can split quite easily. I use a heavy sledge hammer and good wedges. It's a lot easier on the shoulders if you aren't terribly strong, than swinging an axe or maul. I'm not strong enough, I guess, to get the Fiskars to split large rounds for me. However, in a really tough round, they make an impression that is easy to start a wedge in. I use both long wedges with steps on the sides....don't know the proper term....and a square headed twisted wedge. Those, combined with a ten pound sledge dropped from about two feet, do the trick. OK guys, go ahead and laugh. If you are small, you need to improvise. I cut split quite a few cords a year this way. On large rounds, I split along the grain around the outside first. Much easier. Then pie shape splits toward the center.
I would not worry about the saw not being able to handle that wood. Not sure what length your bar is but we cut up 30" and more with a 16" bar and a little 290 Stihl. Does the job nicely. Looks like that park does need some work done on the trees! On that one that is down and limbed, if it were me, I'd cut those limbs closer to the trunk so you don't have those knots to contend with when stacking and especially when filling the stove. The limbs have been cut off already but you can still cut them closer and end up with some small stuff that will be good to burn in early fall when you only want a small fire.
^^^^ Yes, yes I would definitely cut them stubs off flush with the trunk, if you don't you will regret it