Man builds spiral staircase (sketchy) around 75-foot tree

I have no problem with the 2x4's - what do you think your staircase at home is made out of? I have a problem with the 2x4's being nailed into a living thing. When that tree grows, those 2x4's are gonna shift. The staircase will remain viable for a year or two. Beyond that, it's completely unsafe.