[Joshchan]

I use fir bark extensively in orchid growing. For the most part, I have found Douglas Fir bark to be relatively low odor and safe for everything from thumbnail dart frogs to fussy little orchids from the cloud forests of South America. It can get moldy if it gets wet. Usually, if it is of decent quality, it will hold up to high moisture levels for a long time. I try to use kiln dried bark when possible because it tends to have the least amount of active spores and possible aromatic compounds. I have my garter on fir bark now and it seems quite content with the whole thing. I think cleaning is a potential issue however. This is just my experience, your mileage my vary.
Josh