Yup. What he ^ said. Make each cut as far as possible while the big stick is sitting there. I'd start each cut from above, maybe 1/4 way, drive a wedge from above to stabilize, then cut maybe 1/3 through from below. Wedges are your friend, including ones you cut locally.
It's always a good idea to use a cable winch as possible to restrict motion. Winch from one side while you're on the other, cutting. Pick your spots to saw through, pull ond wedge at a time and cut sections free, then cut them up, rolling a/r. Winch can prevent crushing.
You might want to cut off the small poles above the bigger log up front, then below, when freed of big stick. If they're in the way, take them out. This all is still guesswork, not knowing your objectives.
Whatever your plan, make sure it's flexible. Be prepared at all times with Plan B, Plan C, etc. No rush, no ER trips.