Welcome to the forum Timberlake0377. Glad you decided to start posting. You might consider making a new post so this is by itself. With dead wood, it matters if it is standing or down. It also matters if it is touching mother earth or up off the ground. Once on the ground most wood can rot quite fast. Most dead wood also needs to be dried. Some wood, like the dead elm we cut (we wait until the bark has fallen off or at least most of the bark) we find the top half of the tree or sometimes the top 2/3 can be burned right away but that bottom part will be full of moisture even though the tree is usually dead for 3 or more years before we cut it and almost all that wood is still standing rather than waiting for it to fall. Here is some interesting reading for you: Primer on Woodburning by Backwoods Savage | Firewood Hoarders Club You can either read it there or download it in a pdf form.
i see you have more snow than we do here, but with what we just got this morning, i won't do any cutting or splitting. just burning. stay warm.