That's what I thought, too Jim. Kind of neat the way they've gathered the stems together above the plant in the 3rd picture, so they won't hang out into the walkway. I'd love to see that one blooming like that.
Anna, you can use just about any wood to mount orchids on, I think. Aromatic woods like cedar or pine might not be quite as 'friendly' as some other woods, but you can do things like pour boiling water over them a few times to leach out the aromatic oils and 'weather' them somewhat.
It looks to me as if they've sort of made a 'raft' mounting for those orchids, and they've sure taken root nicely.
