Why can't I use resinous wood?

[JKeys]

I've done some poking around online and most guides for mounting orchids warn against using resinous wood for mounts. Just wondering the reason for this - I have some nice slabs of what looks to be wood and bark from conifers that I would like to try mounting plants on.

Thank you!

[gnathaniel]

Hey Jackson, as far as I can tell it's mostly because many resinous softwoods rot very quickly, one of the main criteria for whether a particular wood is unsuitable as a mount. Lack of resin isn't the most useful proxy for durability, though, for example eastern red cedar (Juniperus virginiana) is somewhat resinous but makes excellent longlasting mounts, ditto for the heartwood of some pine species, whereas non-resinous hardwoods like maple, hickory, oak, etc, mostly decay very fast in my conditions. If you post pictures of the wood you have someone here might be able to give you more specific advice about its suitability, but other than managing possible rot complications down the road (too much moisture at the roots, challenges of remounting an established plant), I'd say there's little harm in giving it a try.

Good mount woods I can scavenge locally include red cedar, crape myrtle, rhododendron and laurel, black locust, Osage orange, and sassafras, some of which you may be able to find in your area. Be careful when working with these, sawdust from cedar and rhododendron is toxic/irritating and you might be unexpectedly allergic to a species you haven't previously handled.

[JKeys]

Thanks so much.

[Subrosa]

I'll vouch for osage orange. I processed a tree for firewood for this season and saved several nice pieces of bark, one of which I mounted a D.loddigesii to. It's doing very well, and the wood is second to none for heat.

[Stray59]

I have thought about using cedar and other resinous woods, but my thought on this is that the resin, even a small amount, could clog the velamen of the plant's root, especially under warm, humid greenhouse conditions, effectively smothering the root. Perhaps well seasoned resin wood could work, but again I just use cork bark slabs and hardwoods to mount on.
Just my thoughts.....

[Tindomul]

Cool thread. I never thought of the implications of different wood types. Speaking of Rhododendron mounts, one of my best ones now is from a related genus...manzanita wood, Arctostaphylos. I've had it in my terrarium for 4 years in very wet and humid conditions. It still feels strong.

[Ray]

I think the "avoid resinous wood" thing relates more to its bark than the wood itself.

Many conifers, like pines, for example, secrete a lot of resins into the bark as a way to protect the soft wood from boring insects. The phenols in those resins can be toxic to other plants as well.

Orchiata bark (from a pine) is aged and composted to allow them to break down, while Rexius (fir) is steamed to remove them.

Cedar seems to be fine, and when it comes to deciduous trees, the trick there seems to be finding one that will hold its bark a long time after cutting, or whose wood is porous enough, yet sturdy, to support a plant a long time.

My yard is full of maples, and I find that branches that died, debarked, and fell out of the trees, are very good in the greenhouse.

[ALToronto]

I've used all kinds of wood on my living walls and in other wet applications, and here is what I've found:

Good
All fruit trees
Hardwood maples (silver, Norway, crimson, sugar)
Honey locust
Linden
Elm
Ash
Lilac, if you can get it

Iffy
Aspen
Oak (gets black rot easily, but stays hard for a long time)
Sumac
Soft maple

Bad
Willow
Birch
Poplar
Grape vines
Walnut - excretes a toxin
Conifers - I avoid them all, even though I've seen plenty of orchids mounted on cedar shingles.

If it's not on this list, I haven't tried it. Hope this helps.

[Tschimm]

Grape vines work fine for me... Why do you think they're bad?

[Tindomul]

I don't know all the reasons, but I have heard that the sugar content in them makes them prone to fungal rot in short time. If someone could expand on this?