First a lot of great information provided.
For burn ability, Hedgerow pretty well nailed it. Smaller upper limbs are probably dry enough to burn now with the wood becoming wetter as you work you way down the limbs/trunk.
Split everything 5" in diameter or larger so it will dry faster. Since you are needing wood for this year, keep you splits smaller to allow it to dry as fast as possible. Once you have enough for this year, then you can start having larger splits for future years needs.
With all the big wood you plan on working with, a hydraulic splitter would sure be an asset for you.
As far as the first tree in question:
- Clean up what is on the ground first then work on the standing portion.
- Shallow/open face cut
- Cut part of one side first, then part of the other taking care to listen for wood cracking & the cuts opening up. If you notice either happening, move way back & see what the tree is doing. I have had trees which were hinged, wedges in place & I would just move out of the way & wait for gravity & wind to do the rest. Sometimes it will take a few minutes to happen.
- Keep alternating side to side cutting part way until it starts to go making sure you are cutting from each side & NOT standing behind the trunk. The reason for cutting partway working one side then the other is there is no telling if there is anything in the middle which will help hold the tree up. So by not counting on it & relying on just the sides to have holding power, you will decrease the risk of it doing an unexpected twist catching you off guard.
- Remember when the limbs hit the ground, they will most likely act like springs & sent the butt of the trunk up & backwards maybe to the side so make sure you are far enough away to allow a lot of space for it to move.
On the trees on the ground with root balls:
- Agree the root ball in the photo will want to fall towards the trunk.
- Would start from the top & work towards the root ball.
- Try to position/push as large of chunk of wood as you can under the trunk about 4-6 feet from root ball. Then as you remove the top, it will help hold the trunk off the ground as you work you way down. Once the trunk is off the ground you can just cut from the top off the log downward. Until it is off the ground, cut down from the top, use wedged to keep the cut open. When you get close to the bottom you can either keep cutting downward or switch to an up cut. I prefer to finish with an up cut as it helps me keep the bar & chain out of the dirt.
- When you get down to where the block is used to prop the trunk up, cut 2/3 the way through the trunk for the next set of rounds until you are down to the base. This will leave enough wood to allow you to use a chain /cable to flip the root ball back on to the ground, but will make it much easier to cut them off once it is standing up.
- Remember to use your wedges once it is standing up to keep from pinching the bar. Since you have already cut most of the way before having stood the trunk up, position the wedges to right behind the bar so they will support the last 1/3 of the round you cutting. Then when the cut is completed, the round will drop on the opposite side & open the gap where you finish at.