OK, first things first they say.
In this pic below, you make this cut and the yellow circled area is where most likely most roots which are fed of that leader are and will die.
This is a really bad cut to make, I wouldn't suggest doing it.
Also that's not the worst looking union, it's fairly U shaped not V shaped.
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In this pic, nothing more you can do that making the cut as so and removing that limb. Do not tear off anymore bark! Rope it if need be to prevent any chance of tearing.
Also, in the red circle, clean up those dead stubs properly, cut to target.
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In this last pic, the end of that leader I have circle in red. Needs to be some reduction and thinning.
Try to do that and keep cuts small as possible, under 2" dia if possible. You can head back that main leader to a smaller branch coming off but dont cut off the end where it's say 6" diameter ... only 2" dia and the branch you cut back to should be no smaller than say 3/4" dia where it meets. This is not topping that leader but reducing with target cuts. We dont want that leader growing longer.
When thinning the end it doesn't mean all the little cuts are where the branches join that leader ... it means thin the foliage out as balanced. In this instance I'd say around 25% to 30% combined total foliage removal from thinning and reduction. This will reduce that wind force on such a long lever arm.
When assessing tree failure consequence the value of targets is what dominates. A tree that's going to fail in a totally inaccessible paddock back end ... who cares right. Now that area looks a little low on target value, just think like this ...
1/ If the entire tree failed what would the consequences be?
2/ If that leader failed what would the consequences be?
If the failure of that leader poses a problem then perhaps get some of your rock rope that's dynamic and make a pseudo cabling set up more so for fall arrest, so if the leader does rot and fail it doesn't fall down. Lumi green line to represent. Secure it so it doesn't grip the cambium too strong and make sure there's slack in it enough so that when the wind blows that branch around it doesn't get tight and cause whip lash.
With the loss of that branch and not the whole leader from storm damage proves that leader was stronger. Now you already have reduced sail and weight so I'm not that concerned about the crotch near the ground failing. However with what remain on that leader you have to start some sort of pruning guidance so to keep it short and contained to some degree.
NO LIONS TAILING
