Fla Man missed the concept of taper.

[Isambard]

A good reason why loggers tend to keep the butt ends of logs to the rear. Self-tightening.
Another scenario is in the East, Bamboo scaffolding is always erected with thicker end at the bottom.
So anything tied to it, tightens when slipping down.
Had a brain fade....

[mwmkravchenko]

A good reason why loggers tend to keep the butt ends of logs to the rear. Self-tightening.
Another scenario is in the East, bamboo scaffolding is always erected with thicker end uppermost.

Exactly. Pulled a lot of logs out of the bush. What you mention is indeed the best way. Although those concrete poles are a wee bit smoother than trees!