Removal of trunk from mature co-dominant tree

[ArboristSpencerUnger]

I have an interesting question regarding when you have a dead, diseased or compromised trunk from a multi trunk/co-dominant tree. I was trained as an arborist in Germany and it was common practice in this situation to leave a good sized stump (approx 1/3) of the removed trunk standing to prevent a sudden in-balance and to aid with better compartmentalization of disease and decay. Versus simply flush cutting to the union which seems common practice here in the US. Does anyone have an opinion on this subject? Included two pictures for reference.

 

[ATH]

I'd take the second tree to the ground.

The first, with a sound that big, it WILL introduce decay into the main trunk. I do leave a bit of a stub on those because a wound that large will never completely compartmentalize. I assume the stump slows that entry down. But the day the cut was made, it starty the decay process and that tree is now on borrowed time (but aren't we all!). It needs monitored to check for strength loss. Better be a really good reason to make that cut...

Nobody who knows what they are doing does flush cuts. But it can be hard to find a collar on codominate trunks.

 

[arathol]

That entire tree needs to come down. The right side is already decaying it seems from the picture. Punky looking wood, and fungus growing on whats left of the standing trunk. The left side is almost certainly not much better. As the right side continues to decay the parts below ground will eventually create what is essentially a void, and the rest of the tree will fall. I've seen this happen a few times. One time the second part fell within hours of the other half being removed. Another tree fell in a small windstorm couple months after one stem was removed to ground level. Best to avoid a future problems and do it all at one time.

 

[ArboristSpencerUnger]

That entire tree needs to come down. The right side is already decaying it seems from the picture. Punky looking wood, and fungus growing on whats left of the standing trunk. The left side is almost certainly not much better. As the right side continues to decay the parts below ground will eventually create what is essentially a void, and the rest of the tree will fall. I've seen this happen a few times. One time the second part fell within hours of the other half being removed. Another tree fell in a small windstorm couple months after one stem was removed to ground level. Best to avoid a future problems and do it all at one time.

I completely agree with you. But sometimes the customer or tree inspector request the "healthy" portion to be saved. So in this situation i believe leaving a standing portion of the removed trunk would be your best bet to delay the "healthy" trunk from falling over.

 

[ATH]

Another factor to consider when doing this is that trees are weakest when being twisted. When you take off half like that you may drastically increase that force on the remaining trunk.

 

[ATH]

See article here:
https://tcimag.tcia.org/tree-care/use-your-heading-cut-to-delay-decay/

 

[arathol]

I completely agree with you. But sometimes the customer or tree inspector request the "healthy" portion to be saved. So in this situation i believe leaving a standing portion of the removed trunk would be your best bet to delay the "healthy" trunk from falling over.

The problem here is if half of the tree in the first pictures is removed and you know the other half is ultimately going to fail, there may be ramifications for the guy who did the work if it lands on a house or what ever. Proper notification must be made to the property owner in writing and proper waivers and releases signed to avoid this coming back to bite you. I don't know how liability works in Germany but here a lawyer could have a field day with a situation like this if you don't take the proper precautions to protect yourself.

 

[ArboristSpencerUnger]

See article here:
https://tcimag.tcia.org/tree-care/use-your-heading-cut-to-delay-decay/

Right on! Great article, exactly in line with my thoughts about delaying decay.

 

[ArboristSpencerUnger]

The problem here is if half of the tree in the first pictures is removed and you know the other half is ultimately going to fail, there may be ramifications for the guy who did the work if it lands on a house or what ever. Proper notification must be made to the property owner in writing and proper waivers and releases signed to avoid this coming back to bite you. I don't know how liability works in Germany but here a lawyer could have a field day with a situation like this if you don't take the proper precautions to protect yourself.

Good point