It was a total f*** up and so close to killing the cyclist. They had the gear, big Stihl and you can see the chipper behind the truck just right of the tree. Judging from the fact the canopy had been (presumably safely) dismantled they knew what they were doing, but when it came to that stem they cut corners badly and risked lives. Which will be why the police were after them and I believe IDed them. Health and safety prosecution will have happened, someone ought to have served time for that wrecklesness. The road should have been closed/had lights controlling it and the stem should have been ringed all the way down anyway, the council wouldn't have been happy about the damage that stem would have done the highway.
As for what actually happened, I'm at a loss. The rope and the gob you can see should have had the tree fall along the pavement (sidewalk). You see the guy on the saw playing in the gob then take the saw out and walk away, then the stem goes over perpendicular to the hinge! All I can think is the tree was rotten and the hinge therefore wasn't there, or the cutter somehow cut too far and cut it. But then why he was tickling the back of the gob after having already done the back cut I don't know.
Hark at me! I've never cut a tree in my life.... Know the lingo.... But not much more