This video has been greatly misunderstood, and often demonized..
In part due to the mistaken chronology in the editing, which shows the notch being cut after the line is pulled.. The notch is visible in both sequences showing that it and the backcut were made before the tension was put on like that..
The other part of the misunderstanding is that people make up stories based on limited information.. they see some little part of a job in a video and don't think that there might have been a lot more going on than was shown.. and for some reason, many seem to think its the producers obligation to demonstrate the techniques and calculations used to ensure the safety of an operration..
If you look closely there were four line legs coming off the top of the tree.. , one retainer line and two pull lines... one pull line was doubled.. test pulls were made before cutting the notch, two lower limbs had been cut back to prevent limb lock, again they are visible as the tree stands up..
Load limits were kept to 50-60% tensile.. and mcuh more..
you may think it looks like a "hope and a prayer cut", but it was 100% in my mind.. the only variable was the need to make the final cut. Once the piece stood up, I tried to break the hinge with the retainer (right angle) line. When that failed, I stepped in and cut the holding wood to trip the tree into the field, as I didn't want to lay it up into the trees that were being used as ground anchors.. By the time the tree started to stand up there was less force needed to do the pulling, thus ensuring the ropes would not fail, as they had held at much higher applied force.
Here's another example of similar wok:
[ame=http://www.youtube.com/watch?v=N_z9Lkw8sbI]YouTube - backleaners[/ame]
In case you all haven't seen this one: another couple back leaners..
the firs twas pulled against the lean to free it of the tree it was tangled up in, with intention that the hinge would fail and the tree to drop harmlessly into the yard, as I didn't want it laying up in the anchor trees, or getting the fence..
the second came up and over the creek, before the hinge failed, at which time it fell maybe 15-20º from the intended lay. This was no problem as it did no damage whatever to the tree it laid up in. I had cleared that contingency with my customer, prior to pricing the work. Might have got that one to the lay, had more care been taken with the direction of pull...