Tree "bandage" to help callus or leave it alone?

[SeattleMark]

In past years I've heard that when you trim a limb next to the trunk, you should allow it to gradually and naturally heal with its callus by itself. Now I see an authoritative looking fellow on youtube painting a mixture of orange oil and beeswax on the wound (to help seal it). In my case, I'm taking a large branch off of a cottonwood (which tend to rot easily). Anyone know the latest thinking about simple but effective wound care on trees?

 

[Jim Timber]

I'd let nature do it's thing. However, when doing grafting on apple trees, the joints are sealed to ensure a connection is made and nutrients are capable of flowing to the scion. Beeswax and tar are used on those without ill effect.

This is a green ash in my back yard about 20' from the house. It's been pruned back several times over the 50 years this house has been here, and you can see the marks in the bark from where those have happened. I've got the rope set in it because I'm going to be removing the vertical branch on the left that has 3 rot cavities directly above the trunk (it also supports all the growth above it that ends up rubbing on our roof and gets pruned back every couple years).

I've got 3 other mature ash in the yard which I've taken significant branches off in the past 10 years I've lived here (some storm damage and some to make clearance for the shop build), and all of them have responded with good callous growth. I haven't used any sealant on these (I do on my apple grafts).

 

[ropensaddle]

While at first glance it would appear the dressing was successful. We must examine codit as a whole to see if the sealing process actually had benefit or weather the tree is just a good at compartmentalizing ! I have seen trees with no dressing do the exact thing that video showed with the wood staying hard and only discoloring. It may have helped but more facts and study would need to support it.