OK, so excarnation it is. One would think the practicalities of disposing of bodies would be simple: drag them downwind a decent space and let nature take its course. So the Seahenge solution wouldn't have been the most practical, rather the most spectacular.

We had a Seahenge Tree here for a few years, but it didn't last long. It was fun putting it up, though. The biggest part of the work was stripping off the bark.