In one particular part of the young coniferous plantation, Scots Pine trees are growing in a peculiar manner. This is a shot of an affected tree:
![](http://3.bp.blogspot.com/_tZ447WZizBg/SU_cXjZDy5I/AAAAAAAAAw0/FkGYlfV1XV8/s400/scots-pine-whole-web.jpg)
Note the 'pom pom' effect on the branches.
Here's a close-up of an affected shoot:
![](http://3.bp.blogspot.com/_tZ447WZizBg/SU_dITQUmqI/AAAAAAAAAxM/TBoQMYogX-o/s280/scots-pine-effect-web.jpg)
The damage appears to be caused by clusters of needles dying and dropping off:
![](http://2.bp.blogspot.com/_tZ447WZizBg/SU_c--WJqqI/AAAAAAAAAxE/m-abpuAGiI8/s280/scots-pine-damage-web.jpg)
This shot shows that multiple areas of single plants are simultaneously affected:
![](http://3.bp.blogspot.com/_tZ447WZizBg/SU_cwVLEk7I/AAAAAAAAAw8/WU3g-mt9ju8/s400/scots-pine-area-web.jpg)
I was told that the effect can be caused by the European Pine Sawfly, but my research shows that this sawfly damages needles in a completely different way: by eating them down to the branch. So it looks like I'm back to square one on this one.
Fascinating - is each pompom a year's growth, or are the damaged needles within one year's growth? Are all the affected trees in one area of the wood, in which case I would suspect some soil/water environmental effect (and in that case I might also expect other vegetation in the area to show peculiarities as well).
ReplyDeleteI have seen trees patchily defoliated (but not neatly like yours) in other places but that has been down to acid rain which I would not imagine is a problem in Donegal. Plain rain of course is another matter :-).
Intriguing - watch this space!
And Happy Christmas!
Each gap appears to be a single year's growth...from a previous year. This started on one tree and is spreading outwards to neighbouring trees, so I think it's a pathogen, not environmental. Defoliation is never complete: there are always pompoms left. Wonder if it's fungal (I have a sample with dead needles on it on a slide...I'm waiting to see if there are any spores).
ReplyDelete