Ash wood for mounting

[Tom_in_PA]

Ash is a very hardwood so rotting to fast I suspect will not be an issue

[Swamper]

that looks a lot like the popash tree found in the fakahatchee strand, where it spends a lot of time wet and hosting a lot of orchids. The ghost orchid in particular love it. I wish I had one in my yard, it would be INFESTED with orchids.

[epiphyte78]

Nice textured bark...the ash trees around here all have very smooth bark...which dries out too quickly in our dry climate.

My vote would be to leave the branch on the tree if at all possible and mount orchids on it like Swamper mentioned. Well, depends on where you live. If you live in zone 8 or above, I would try to mount a test orchid on it to see how it responds to the wood. You should do that even if decide to take the branch off.

[Swamper]

Yes, where do you live?

[Ross]

Being a northerner myself and retired from the US Forest Service, I happen to know something about northern white ash (no doubt, your tree). It is not particularly rot prone, but constant moisture will shorten the life of the mount (unlike cedar). I would for sure strip the limb of the bark. The Emerald Ash borer may be present. It lives just under the bark in the cambian of the tree. Also, the bark has much less resistance to decay. There isn't any way to preserve the bark structure that would be safe for the orchids. How wet will the chunk of wood stay? Daily mistings or even dunkings are fine as long as the limb dries out overnight. I really think the whole project is worth undertaking as long as the bark is gone. To be on the safe side, I would air-dry the chunk you select for several months before mounting the orchids. There is no chemical in the wood that will cause harm to orchids.

[epiphyte78]

There's definitely more than one way to mount a Catt... but personally, I prefer to leave textured bark on the branches. It helps retain moisture and provides more root holds for the orchid to cling to.

Once the bark separates from the wood, the orchid roots enjoy the additional moisture to be found between the wood and bark. Also, I'm fairly certain that the gradual decomposition of the bark provides some nutrients for the orchid. Though I haven't the faintest idea which nutrients or in what quantity. I've never fertilized my orchids and they grow just fine.

In my experience, most wood mounts are going to last at least three times longer than the average orchid needs to be repotted. From personal experience, by the time the mount starts breaking down, it's about time for the orchid to be divided anyways and it's fairly easily removed from the broken down mount.

As a reference, here's a photo of a NOID Catt that I mounted a couple months ago on a very old dead wood fruit tree branch.