Hewing a thick spruce with Gransfors broad axe (part one)

I´m hewing a thick spruce log without making any cuts in the sides first. It´s an experimental work to hew a log the old way (from an old photo I have seen). I have just stretched a string to cut after. I´m using a Gränsfors broad axe (www.gransfors.se) and I am surprised how durabel the edge is when I cut those hard spruce twigs.