cutting back of a large branch to the trunk

[JimM]

Slightly similar circumstance a year ago. Ash limb knackered to about 4 ft from the lower stem. Wound at the stem would have been just over 2ft diameter. I elected to leave a clean stub just over 3ft long and monitor. The rest of the tree isn't great, so it was more of a way to prolong the inevitable as said above. I've had a few comments about its look though.

[MattyF]

My take on it is slightly different.

 

For starters if you are removing such are large limb from the tree I would imagine this would comprise more than 30% of the foliage, which is going to detrementally impact the tree anyway. Also if you cut back to a stub, even if it regrows with epicormics, it will not compartmentalise. The decay will be met with less resistance at a stub than at a collar due to a lack of barrier zones. The decay will engulf the stub and will have a higher chance of penetrating the barrier zones in the collar (admitedly at a much later date) because it will have gained momentum devouring the stub.

 

I think you shoud avoid removing the limb if there is an alternative, but by leaving the stub you are delaying the inevitable. Some pictures would be great, the tree sounds big!

 

 

There is no way on earth it will ever compartmentalise on the collar ,ash and will be Inonutus fodder within 7 years and the tree structurally be more compromised,

If a 6meter stub carries on living it will slow it down and give it atleast another 10 years and maybe more and I have even seen ash stop decay at barrier zones like this with storm damage and pollarding but never exposed through collar cutting.

If it does die you have a more cleaner view of where the collar is any way.

[Fredward]

And think how much energy the tree will waste trying to keep alive a giant stub! Fair enough I'm not familiar with the pathogens at work in the locale but I was taught that leaving excess branch material after the collar is a bad thing.

[MattyF]

Ash seems quite happy throwing out vigorous epicormic if there's still surviving canopy.