They are called excavator mulchers, but that's an understatement. What they really do is swallow trees. The video is 3 minutes, but you really only need to see the first 15 seconds, which is the time it takes the mulcher monster to consume a 9 meter-tall, mature spruce – starting at the top, landing at the bottom.
The tree that was, suddenly isn't. Technosphere vs Biosphere: 1-0, it seems. But then you calculate how many trees need to be burned to provide the mulcher with enough energy to swallow one tree. Not entirely cradle to cradle. We wonder if the monster mulchers also do Antenna Tree masts.