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David Humphries

Chalara fraxinea - Generic thread

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On 22/06/2019 at 13:47, EdwardC said:

On a more positive note, it doesn't appear to infect olives.

That's not a positive note. Olives are akin to engorged ticks and should be incinerated for biosecurity reasons. I have no doubt that Xylella fastidosa was knocked up by someone who knew what they were doing, for the greater public benefit 🤮 

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16 hours ago, Adam M said:

That's not a positive note. Olives are akin to engorged ticks and should be incinerated for biosecurity reasons. I have no doubt that Xylella fastidosa was knocked up by someone who knew what they were doing, for the greater public benefit 🤮 

Heathen ! 🙂

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This may not be the precise best place to post this. However I've spotted an Ash nearby to my home that is exhibiting some significant foliage stress. I've taken a sample and it does not seem to be emenating from the leaf veins as per ADB rather from the leaf margin. 

I'm interested in what this could be for obvious reasons. The tree stands imediatley next to another which is not showing these signs of foliage stress. 

My next thought was verticillium wilt but it doesnt appear to match images I can see from a quick Google. 

All thoughts and theories welcomed. 

O

IMG_20190816_202534.jpegIMG_20190816_202544.jpeg1566145649959.jpeg

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IMG_4539.jpgIMG_4540.jpg

Yesterday I had to fell a reasonable sized Ash tree that was showing advanced signs of ADB. I had heard that the disease shortens the wood fibres and makes them weaker. When I looked at the hinge I would normally expect on a healthy Ash to see menacing looking pointy needles of fibre sticking up but on this one the fibres were indeed shorter and blunter. I certainly wouldn’t want to fell one with a significant lean in the wrong direction.

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3 hours ago, jonnygurkha said:

IMG_4539.jpgIMG_4540.jpg

Yesterday I had to fell a reasonable sized Ash tree that was showing advanced signs of ADB. I had heard that the disease shortens the wood fibres and makes them weaker. When I looked at the hinge I would normally expect on a healthy Ash to see menacing looking pointy needles of fibre sticking up but on this one the fibres were indeed shorter and blunter. I certainly wouldn’t want to fell one with a significant lean in the wrong direction.

I don't get this!

I could kind of accept that local to the point of infection there may be some changes in wood characteristics but even with advanced dieback within the crown I can't imagine it would alter the base of the stem.

 

My thoughts are based on how trees react to the DED fungus, compartmentalising infected twigs, tertiary and secondary branches - a progressive compartmentalisation process. I imagine that ash reacts in a similar way.

 

Could it be that as the vascular function diminishes with the loss of foliage/water uptake the lower moisture levels reduce the strength of the wood fibres in tension? I dunno :confused1:

 

The FISA guidance I read this week (IIRC) focused more on not using wedges for felling due to the vibrations causing dead limbs to fracture. Can't remember much about short grain when felling.

 

EDIT. Would/could drought conditions alter 'fibre strength'? Could there be a relationship there? 

Edited by Gary Prentice

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1 hour ago, Gary Prentice said:

I don't get this!

I could kind of accept that local to the point of infection there may be some changes in wood characteristics but even with advanced dieback within the crown I can't imagine it would alter the base of the stem.

 

My thoughts are based on how trees react to the DED fungus, compartmentalising infected twigs, tertiary and secondary branches - a progressive compartmentalisation process. I imagine that ash reacts in a similar way.

 

Could it be that as the vascular function diminishes with the loss of foliage/water uptake the lower moisture levels reduce the strength of the wood fibres in tension? I dunno :confused1:

 

The FISA guidance I read this week (IIRC) focused more on not using wedges for felling due to the vibrations causing dead limbs to fracture. Can't remember much about short grain when felling.

 

EDIT. Would/could drought conditions alter 'fibre strength'? Could there be a relationship there? 

We could do with members posting their pictures of  larger ADB felled trees as Jonny has done, and see if they are similar characteristics.

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Just now, Paul Cleaver said:

We could do with members posting their pictures of  larger ADB felled trees as Jonny has done, and see if they are similar characteristics.

Seems like there are a lot of unknowns with this disease, so every ones experiences and observations are useful and would go towards a better understanding. Good idea Paul 

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I have spent a couple of days this week felling oversize diseased trees. Tbh any decay at the butt end could have been expected of trees of that size on that particular type of ground. 

I have felled a few parcels now , and certainly from a felling point have seen little difference in how the trees respond to non diseased trees.

I did take photos ,but sadly they are of poor quality and would be of little value to the discussion.

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I have mentioned a few posts back the observations we found when recently felling 550+ Ash with ADB, some with poor crowns, some completely gone.

I would estimate that 50 percent had some basal decay but no external sign/fungus present on the butt, these are plantation trees, not coppice stools and drawn up well in a mixed Beech compartment, no drought issues have been noted in any other tree species in this compartment, so why would drought only effect the Ash?

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I manage and work in a woodland in North Devon. We have quite a few ash in certain parts of the site. During the summer I had noticed a few showing signs of dieback, but have now noticed quite a few completely leafless crowns. Would you assume that they are dieback and remove if in a high traffic area and if safe to do so or would you expect some ash to have completely lost their leaves at this time of year?

Thanks for any thoughts

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