Basically, two of my dwarves mysteriously got transported onto trees.
First one is a herbalist, who was stuck 2 z-levels above ground. The other is a miner, who has somehow managed to end up 7 z-levels above ground on an adjacent tree.
The only clue I could get as to how this happened was in the reports. Apparently there was a mantis man on the tree, 1 z-level above ground who tried to grab the miner . The miner amputated and decapitated him effortlessly and delivered a few one-liners to boot.
After "zooming to location" from the reports tab, I ended up here at level 144, 1 z-level above ground. You can see the mantis man's corpse there, on the branches of a peach tree.
The herbalist was stuck 1 z-level up from the mantis corpse (i.e. 2 z-levels above ground) on the same peach tree. He played no part in the conflict with the mantis man, but was distracted by a mantis woman while gathering plants (no attacks though, so nothing in the reports).
The miner ended up 7 z-levels above ground at level 151, on a walnut tree next to the peach tree.
While all this was going on, the dwarven caravan had been unloading at my depot. Now they're just sitting at the depot with all their goods unloaded, but I can't trade with them. Scanning the depot with "q", it says "There are no merchants trading right now".
There is also apparently a "missing" wagon according to the units tab, a wagon wood log sitting in my wood stockpile and a merchant with a yak and a guard standing around 1 z-level below the depot. The guard had shot a bolt at the mantis man earlier.
Can anyone explain what the hell just happened?
Edit: Felling the tree just causes the dwarf to fall down to the ground and get crippled/killed. Also, when I tried constructing a staircase straight up through the tree (i.e. on the same tile as a branch or twig), the dwarf on the "construct building" job would pick up the block and just stand at the block stockpile without moving. Constructing floors on those tiles worked fine however.