This would have been an interesting video for the masters of old Japan to view. What you've got is basically a three pound razor blade that is being pushed to a high velocity by a strong person. I suspect that the average fighter back in the vintage days of Japan was quite a bit lighter than Dan. His upper body power is a major factor here. He can generate much more force than the average individual which contributes to the sheer power of the cuts.
Back in Manila, the 'Tuguegarao' test knives in a similar fashion although they are one handed machete style blades of rural heritage. The modern iterations sport crude handles made of discarded rubber tires which represent a simpler construction than the traditional buffalo slabs. The locals test their bolos on a regular basis although their competitions are not organized or published. I wonder how many trees have suffered ill from their knives?
The Sengalese used their 'coup-coup' in the same way. These were stamped out by a trivecta of companies, notably Dumas. It is frequently mentioned in historical accounts that the Germans feared this weapon and tried to avoid a confrontation with these at all costs. Many trees were chopped down with these formidable weapons. Hand to hand combat was fierce and was over in a flash.
Kuks of every imaginable size and style have been utilized in the tree chopping mode. One huge example of this venerable blade is used in taking the head of a water buffalo in one fell swoop. Trees are routinely cut in rural areas where the kuk is more popular and readily available than the axe.
Dan has produced a great blade that is again, quietly revisiting those age-old testing grounds where men like to venture. How deep can we cut? How awesome and fearful is this weapon in battle? Back in the distant past of Japan, a great master is smiling.