Cause for one sided dieback on Oak tree?

[Steve Bullman]

Interesting Picus test yesterday on this roadside Oak tree. One side of the tree has died back almost completely with no obvious reason. No fungi at base. Lots of delaminating bark, had to remove a small piece to get a sensor in. 

 

Picus showed severe decay on just one part of the tree which was also the same side as the dieback. Delaminated bark extended up trunk and I suspect it may be decayed a considerable distance up the trunk which may account for the dieback just on this side of the tree. Other side of the tree appears healthy although there are some sizeable pruning wounds so its possible dieback was removed recently.

 

Interested to hear thoughts on what might be at play here. Any suggestions @David Humphries @daltontrees

 

[JonnyRFT]

Any stem bleeds and/or exit holes? Perhaps AOD?

[Steve Bullman]

Just now, JonnyRFT said:

Any stem bleeds and/or exit holes? Perhaps AOD?

Nope. Only external signs I could see was the obvious dead portion, and the delaminated bark

 

[Steve Bullman]

Would AOD just take out a single stem like this?

 

[Dan Maynard]

Can't see root flare, is it under the grass or under the soil? Seems to me needs to be something big to take out so much of the tree, root excavation/damage?

[openspaceman]

15 minutes ago, Dan Maynard said:

Can't see root flare, is it under the grass or under the soil? Seems to me needs to be something big to take out so much of the tree, root excavation/damage?

I was thinking soil made up on that side for that very reason.

[JonnyRFT]

11 hours ago, Steve Bullman said:

Would AOD just take out a single stem like this?

 

I had a large Oak down in Framlingham with AOD, in a similar overall condition. However, by pairing the stem bleeds with the exit holes, it was an almost certain diagnosis.
If there’s nothing of the sort in your case, then I would be looking for root dysfunction. What size was the RPA? Is there any scars in the ground within it, to suggest trenching, compaction or such like has occurred? 
 

As suggested above, soil level changes could be the culprit too.

 

 

[Suffolk Dave]

I would think and agree , may be root damage sometime ago on the die back stem side., any idea how long the die back has been taken place?

[daltontrees]

Looks like old damage, and as has been said niticeable absence of flare. I have no experience of interpreting Picus. It looks like decay following damage rahter than teh other way around. Old impact, fire, major root severance by services close-in?

[Steve Bullman]

18 hours ago, Suffolk Dave said:

I would think and agree , may be root damage sometime ago on the die back stem side., any idea how long the die back has been taken place?

I did a Picus on the same site 4 years ago and don't recall seeing it then. I'd have thought it would have been picked up on the general report if it were dead then.