In our local Bonsai group the experts have recipes for soil that uses pine bark. With orchids we use fir bark (I read on the west coast people use redwood bark?); some people use cork bark.

Anyway, I wonder if there is a better bark to use than another for particular plants? Is it preference, availability, or something one type of plants needs that is found in a specific bark like a trace element or some microbial that prefers one over another? All barks of course must be aged/composted so they don't rob nitrogen, but outside of that I have no idea what one would bring to the party over another.

I use different things in my mixes for structure, aeration, & water retention depending on the needs of the plant and the type of container. In the ground I generally just use compost but I'm curious about potted/containerized improvements and if one bark would be better than another. I've always looked at bark as just a carbon source that retains some water, aerates, and benefits microbes as part of a food source. I certainly don't want to complicate my gardening but if types of plants do better with one bark over another it might be an excuse to experiment a little.
Any thoughts?

Fir bark, fern bark, cork bark, packing peanuts and wine bottle corks all make good orchid medium because they don't absorb water readily and decomposes slowly. A little pine bark in the bonsai mix adds water retentiveness and slow release nutrients. Orchid growers use pine bark in a pinch - it breaks down too fast.

Orchid growers sometimes add a little redwood bark or cypress bark to their mixes as it lowers the Ph and decomposes slowly.

Thanks, Daisy!
I've always stuck with pine bark for bonsai and fir for orchids, but only because "we've always done it that way". I like having a bit more to go on than that. One of my orchids (Brassavola cucullata) is mounted on a piece of cork and it is a very happy little camper. It loves lots of air circulation so cork works nicely for water retention and the roots grow onto it readily.

This information will help with what I want to do with mixes for various potted plants. I appreciate the help!