Why is it important to you that the logs be oriented vertically, Nathan? I don't see the advantage, and Bill et al. have pointed out a number of detractors, some of which might be cost-prohibitive to address with the logs standing on end.
I love the idea. Of
course, when I started into the brief, I had it in mind that you were thinking tower instead of yurt, and I have wanted a tower ever since as a young reader I got lost in David and Leigh Eddings' worlds of fantasy.
It occurs to me, though, that, short of getting a livingspace high up off the ground, like a watch tower or
water tower structure, where there's a lot of airspace underneath, and the structure is its own separate pod, the structure you're suggesting, or even the log-cabin tower I had started envisioning (thanks for that, by the way; now I'll have to build that, too) is better constructed as a conventional log structure with horizontally-laid logs. If you wish a round structure, the effect can be achieved by using a many-sided polygon. Octagons are by far the simplest, mathematically speaking, or at least that's been my
experience, working with materials that, oftentimes, are based on a 4'x8' standard.
By the way, one reason why end-rot was less of an issue for your typical palisade construction was that one end was invariably buried several feet in the ground. No oxygen, no rot. And that's before they started using lime or
wood ash to preserve the post ends.
As to end-rot prevention, I am currently playing around with ideas for converting a heat-based paint scraper into a yakisugi tool. I haven't seen it done that way, but I honestly haven't seen a wood preservation method I like better than charring large pieces under controlled circumstances such that the structure remains sure, but the few millimetres of char on the surface inhibits all microbial growth.
In any case, please keep us posted, and best of luck to you.
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein