Taking down a massive dead tree - GIF

Taking down a massive dead tree.

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Previously:

Bear emerges from chainsawed trees - GIF
Cutting a felled tree in two in one go - GIF
Cutting down a tree burning from the inside - GIF
Enormous bandsaw mills slab off of tree - GIF
Laser tree trimmer - GIF
Lightning destroys tree - GIF

I want to know how they did that. That's a big saw, but it still doesn't look big enough to get to the middle of that tree.

There is another saw on the ground that looks to be longer...