In those forested (none of these sites were near targets such as houses) situations, some of the trees are hung up, jackpotted, or rotten to the point where having a faller sitting at the bottom of the tree is dangerous. Often in the past, fallers would try and use another tree to push over those danger trees. This is just another tool in the toolbox for getting the job done.
This is a marketing video, aimed at forest companies and contractors who operate in areas of the BC Coast which are too steep and rugged for mechanical falling (faller bunchers).
After a number of faller deaths in a short period of time a few years ago, the politicians got involved and has lead to a number of new regulations. For example, you must be a certified faller to fall any tree greater than 8" diameter. Arborists can get around this by using proper arboriculture techniques ie line in the tree, climb. Faller certification costs $1500 to challenge the exam, $9000 to take the course. The certification is entirely geared to production forest falling.