Can I prune this tree on the right and left? Should I wait until the winter or spring? Tips on pruning.
The white arrows look like codominant leaders with included bark. Your choice is between the lesser of two evils. If you prune it, that's going to make a nasty wound that will take years to compartmentalize and if it gets colonized by insects of aggressive pathogens it may kill the tree. But if you leave it alone, years later (when it's much larger) it will break off in a windstorm and that will lead to the death of the tree.
The blue arrow looks like a branch with a good bark ridge on top. Pruning it has a much higher chance of success.
Can you take a focused close-up of both areas?
"Should I wait until the winter or spring?"
I would prune in later winter before bud break. That will minimize the time it takes (a few months if done correctly on a vigorously growing tree) for wounds to cover over. It will also allow you to better see what you are doing, as there won't be any leaves in the way.
"Tips on pruning."
There are many, many posts on that topic already. Do a quick search and you'll find more than you can read in one night. Also, there are many good sites on the web. The ISA's site, www.treesaregood.com, has some good explainations here and here.
One thing that you could do for the co-dominant leaders, shown in your picture, is reduce the one you want to eventually remove, and then remove it in a few years after a good branch collar has had time to form. This treatment has been covered a number of times here in this forum, and maybe someone will find an example and post a link. If not, maybe I can come back later and give you more info.
"Your choice is between the lesser of two evils. If you prune it, that's going to make a nasty wound that will take years to compartmentalize and if it gets colonized by insects of aggressive pathogens it may kill the tree."
WOW!!! If I thought this way about trees, I'd just move into a condo in the heart of the city where all I could see was blacktop and buildings.
> brandon7 7 TN Sat, Aug 9, 14 at 22:24
> One thing that you could do for the co-dominant leaders,
> shown in your picture, is reduce the one you want to eventually remove,
> and then remove it in a few years after a good branch collar
> has had time to form.
It sounds like you are saying a branch collar will form around a codominant leader that has included bark. I wasn't aware of that. If that's what you meant, could you please provide a link to an authoritative source?
Tenacre, you should be able to google something along the lines of 'subordination codominant leader' and find plenty of info and references.
brandon7 7 TN Sun, Aug 10, 14 at 1:27
>Tenacre, you should be able to google something along the lines of
>'subordination codominant leader' and find plenty of info and references.
Thanks for the search terms. I found a lot of useful and interesting information.
I did not find any sources that said a branch collar would form around a subordinated codominant stem that has included bark. Shigo never mentions that happening in any of his books I've read. Do you have any before & after pictures?
Nope, I don't have pictures. If you think about how a branch collar is formed, whether you consider a strict Shigo explanation or newer explanation, I think you'll easily see that a branch collar would form on a subordinated leader. Multiple arborist chat forums discuss experiences with branch collars forming on subordinated leaders (turned branches).
Once you make that subordination cut in late winter you'll want to do the cut to the trunk just outside the branch collar in June so it doesn't leak like a sive with such a big wound in late winter. It will heal nicely with that timing. I would have cut that co-dom back already but its too late right now.