Rowan tree stem hollowed

mark.i.lansdell

Can any one help identify this problem with a Rowan tree? It is a fairly young tree, having reached only about 7ft in height. In the recent winds, the central stem (i.e. trunk - just seems too thin still to call it that) broke about 2ft from the top. On inspection, I discovered that the stem was substantially hollow at the point of breakage.

The first two photos below show a short section of the stem that includes the breakage point. You can see that approximately half the stem has been hollowed out (it was about two thirds hollow at the breakage point itself). In contrast, there was not much hollowing in the trunk below the breakage point (I removed only another inch or so of trunk below the breakage point to get to what looked like healthy wood across the entirety of the cut).

The third photo shows the condition of the stem slightly higher up from the section in the first two photos. You can see in this photo that there is a channel where the wood is being turned to a red-brown wet pulp.

The final photo is yet higher up the original stem, at which point the channel is more circular in shape. An hour or so after making the cut, I think I briefly saw a maggot appear at the opening of this hole, but it disappeared back in side before I could capture it on camera, and I can't be sure it was there at the time of making the cut.

I presume the problem is some sort of tree-boring species rather than a fungus or bacterium. I've tried googling, but every website describing tree-boring species in any useful level of detail seem to be US-centric, so I'm struggling to identify what could be the culprit here in the UK.

Thanks in advance for any help.

Mark

nutcutlet

I am interested in the first 2 photos which appear to show a branch previously cut off to about 6 inches. This may be a trick of the camera and not so. But leaving short branch lengths when pruning causes the stub end to rot and this spreads to the main trunk. Always cut back to a joint or a bud, trees have a circulation (for want of a better word) and a stub end is left with no life.

Fairygirl

I'm struggling to make sense of the photos, but I'd agree with what @nutcutlet says re cutting back. Did you cut off the damaged parts each time?
If this major damage is further up, as you're indicating, it suggests the tree isn't happy in the site it's in. Rowans are pretty straightforward, but they do get damaged in exposed sites, so if it's getting wind damage, it may need repositioned.
Rowans love loads of rain, but they won't appreciate being waterlogged long term, so that could also be a factor in it's health.

How is it growing, and where @mark.i.lansdell ?  Is it in the ground? 

mark.i.lansdell

Thanks for the comments and questions. Yes, it's in the ground. The tree stands on the north boundary of our garden, at the end of a hedgerow. The boundary is with an open field, so it does get plenty of northly wind, though there are four other Rowans (aged variously 5-15 years) along the boundary that have grown well since we planted them and that remain healthy. However, this is the third Rowan that we have tried to grow in this particular spot. The first two died within two years of planting. This one has been in the ground about 5 years and previously I had thought it had overcome the curse of that location. Maybe it's just not meant to be.

Apologies if the first two photos were confusing. I was using a couple of branches to support the small section of trunk of the tree that I had removed so that I could easily photo the hollowing out. It is specifically what is causing the hollowing that I was most keen to identify. But yes, you are right to spot that there was a short stub on the trunk close to the breakage point. A slender branch there had snapped a couple of years ago (apart from that, the tree had not been pruned till today). Possibly, how I left it was my error.

Fairygirl

It's possible that the site just isn't suitable, compared to the other areas, but it's virtually impossible to judge without being there in person. Generally, in windy sites, they just grow lower, and get a bit stunted, but they can be damaged by drought or really bad drainage.  It sounds as though there's something else going on. Are there animals in the field, or deer etc who can access it?
A wider view of the site might help too. 

The 'boring' insect is more likely to be harmless, and just jumping on the bandwagon  - ie it's making the most of a good food opportunity. 

bédé

Definitely rot.  You may never find the cause.  You can do no better than to cut back to good wood (following the advice not to leave a dead-end) and hope.

Is it just a wild Rowan  or is it something more special?