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Online Lionel Hutz  
#1 Posted : 12 June 2019 09:56:32(UTC)
Lionel Hutz

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Joined: 05/04/2006(UTC)
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Ireland

A sign of the times that we have two separate threads about tree disease. I have been reading about the horse chestnut bleeding canker in the UK for some years. I knew that it had reached Ireland but hadn't seen any evidence of it. This year, however, most of the horse chestnuts near me seem to be in a bit of trouble. However, I am hoping that it's not canker. Firstly, I assume that canker takes a coupe of years to get hold of a tree and that it tends to affect leaf growth more as the growing season proceeds. In the case of the chestnuts near me, they had no problems at all until this year. Furthermore, the problems developed right at the start of the growing season with only about half of the leaves in the section affected coming into leaf. I say section affected as it only seems to affect at most half of the trees in question, with the remainder of the trees the same as normal. There is no evidence of the bleeding associated with canker. Does anyone have any idea what this is? Is it the early stage of some widespread disease like canker or just something local?  

Lionel Hutz

Nr.Waterford , S E Ireland

68m ASL

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Offline Roger Parsons  
#2 Posted : 12 June 2019 10:36:43(UTC)
Roger Parsons

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Location: Lincolnshire

Originally Posted by: Lionel Hutz Go to Quoted Post

A sign of the times that we have two separate threads about tree disease. I have been reading about the horse chestnut bleeding canker in the UK for some years. I knew that it had reached Ireland but hadn't seen any evidence of it. This year, however, most of the horse chestnuts near me seem to be in a bit of trouble. However, I am hoping that it's not canker. Firstly, I assume that canker takes a coupe of years to get hold of a tree and that it tends to affect leaf growth more as the growing season proceeds. In the case of the chestnuts near me, they had no problems at all until this year. Furthermore, the problems developed right at the start of the growing season with only about half of the leaves in the section affected coming into leaf. I say section affected as it only seems to affect at most half of the trees in question, with the remainder of the trees the same as normal. There is no evidence of the bleeding associated with canker. Does anyone have any idea what this is? Is it the early stage of some widespread disease like canker or just something local?  

Hi Lionel - thanks for this. On 25th May I included the following "Tree diseases and Pests" link in a post about Ash Die-back.

https://www.woodlandtrust.org.uk/visiting-woods/tree-diseases-and-pests/key-threats/

I don't know much about about Horse Chestnut canker, but the Woodland Trust page about it is helpful if succinct.

https://www.woodlandtrust.org.uk/visiting-woods/tree-diseases-and-pests/key-threats/horse-chestnut-canker/

For further information it refers the reader to the Forestry Commission website:

https://www.forestresearch.gov.uk/tools-and-resources/pest-and-disease-resources/bleeding-canker-of-horse-chestnut/

Hope this is helpful.

Roger

 

RogerP

West Lindsey district of Lincolnshire

No county (Lincolnshire) has better churches and worse houses. The poorer sort of people wash their clothes with hog's dung, and burn dried cow's dung for want of better fuel; whence comes the Lincolnshire proverb: "Where the hogs shite soap and the cows shite fire".

Curiosities of Great Britain (c.1780)

Online Lionel Hutz  
#3 Posted : 12 June 2019 11:29:46(UTC)
Lionel Hutz

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Joined: 05/04/2006(UTC)
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Man
Ireland

Originally Posted by: Roger Parsons Go to Quoted Post

 

Hi Lionel - thanks for this. On 25th May I included the following "Tree diseases and Pests" link in a post about Ash Die-back.

https://www.woodlandtrust.org.uk/visiting-woods/tree-diseases-and-pests/key-threats/

I don't know much about about Horse Chestnut canker, but the Woodland Trust page about it is helpful if succinct.

https://www.woodlandtrust.org.uk/visiting-woods/tree-diseases-and-pests/key-threats/horse-chestnut-canker/

For further information it refers the reader to the Forestry Commission website:

https://www.forestresearch.gov.uk/tools-and-resources/pest-and-disease-resources/bleeding-canker-of-horse-chestnut/

Hope this is helpful.

Roger

 

Thanks, Roger. I missed that link in the ash dieback thread. On balance, I don't think that the canker is affecting the trees here. It could simply be some local pest. A lot of the Sitka spruces in our wood(we have a small number of them) have been hit by this https://www.teagasc.ie/crops/forestry/advice/management/green-spruce-aphid/ so hopefully, our horse chestnuts have been affected by something non fatal like that.

Your link is certainly concerning. I wasn't aware of the seriousness of the red band needle blight. Lots of threats out there.

Edited by user 12 June 2019 11:34:54(UTC)  | Reason: Not specified

Lionel Hutz

Nr.Waterford , S E Ireland

68m ASL

Offline Caz  
#4 Posted : 12 June 2019 18:52:25(UTC)
Caz

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Location: Market Warsop, Nottinghamshire, East Midlands

I’m wondering how many of these tree diseases are really new, or whether they’ve been around for a long time and we simply know more about them now.  Organisations such as the woodland trust are relatively new and we therefore have more monitoring of trees, so maybe we’re just more aware of the problems now.  I don’t know.  It’s just a thought!

Market Warsop, North Nottinghamshire.

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Offline Devonian  
#5 Posted : 12 June 2019 19:46:26(UTC)
Devonian

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Originally Posted by: Caz Go to Quoted Post

I’m wondering how many of these tree diseases are really new, or whether they’ve been around for a long time and we simply know more about them now.  Organisations such as the woodland trust are relatively new and we therefore have more monitoring of trees, so maybe we’re just more aware of the problems now.  I don’t know.  It’s just a thought!

All of them. Ash die back, Dutch elm, Phytophthora - all new. I can't think of any one (that is serious) that isn't. Box blight maybe?

"In a 52-48 referendum this would be unfinished business by a long way"

Nigel Farage, Daily Mirror, 16/5/2016

"I think the mistake the government made - led by Theresa May - from the start was to try and claim that a country that had voted 17 million to leave the EU, 16 million to stay, wanted a 100% Brexit"

Osborne, 22/12/18.

Offline Caz  
#6 Posted : 13 June 2019 03:26:52(UTC)
Caz

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Location: Market Warsop, Nottinghamshire, East Midlands

Originally Posted by: Devonian Go to Quoted Post

 

All of them. Ash die back, Dutch elm, Phytophthora - all new. I can't think of any one (that is serious) that isn't. Box blight maybe?

Do we really know that for certain though Dev?  The names might be new but do we know such diseases haven’t struck before, possibly under a different name, or no name at all if there was little awareness. We are far more conscious of our environment these days and have better understanding of the science and better means of communicating. 

Market Warsop, North Nottinghamshire.

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Offline Roger Parsons  
#7 Posted : 13 June 2019 06:19:01(UTC)
Roger Parsons

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Location: Lincolnshire

Originally Posted by: Caz Go to Quoted Post

Do we really know that for certain though Dev?  The names might be new but do we know such diseases haven’t struck before, possibly under a different name, or no name at all if there was little awareness. We are far more conscious of our environment these days and have better understanding of the science and better means of communicating. 

Plant pathology is a well-trodden path of scientific research, but I am no expert on it, Caz. I am only conscious of the many aspects I do not know - no change there. Science certainly teaches humility! However, I do have some background in Animal Diseases and offer you this thought to stand alongside your questions.

In considering how any disease works, the basic model is what is known as an "epidemiological triad". This looks at 3 interactive elements of the biology of disease, the "agent", the "host" and "the environment". A change in one of more of these can and often does affect the way in which the disease changes and develops, becoming milder or more virulent, spreading in new ways etc. You can widen the model to include a "vector", which is also subject to interactions. I recommend this way of looking at any disease.

There are two other considerations to tuck away for future use. Firstly - a "good pathogen" does not annihilate its host - that would be evolutionary suicide unless it had an evolutionary "plan B"! Secondly - in seeking a treatment or cure you need to take into account all 3 elements of the triad.

I hope this makes sense. Here's an OU introduction I have just googled for the diagram. The topic is not very relevant but the methodology is.

https://www.open.edu/openlearn/science-maths-technology/science/health-sciences/epidemiology-introduction/content-section-3.1

Roger

Edited by user 13 June 2019 07:46:42(UTC)  | Reason: typo

RogerP

West Lindsey district of Lincolnshire

No county (Lincolnshire) has better churches and worse houses. The poorer sort of people wash their clothes with hog's dung, and burn dried cow's dung for want of better fuel; whence comes the Lincolnshire proverb: "Where the hogs shite soap and the cows shite fire".

Curiosities of Great Britain (c.1780)

Offline DEW  
#8 Posted : 13 June 2019 06:28:24(UTC)
DEW

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Originally Posted by: Caz Go to Quoted Post

Do we really know that for certain though Dev?  The names might be new but do we know such diseases haven’t struck before, possibly under a different name, or no name at all if there was little awareness. We are far more conscious of our environment these days and have better understanding of the science and better means of communicating. 

If you search 'Elm decline' pollen records show a dramatic drop in the elm population at 4000 BC and again to a lesser extent 1000 BC. Dutch elm disease is suspected but not proved.

Other diseases are not new globally but have arrived here as a result of global trade e.g. phylloxera on vines from US, chalara on ash from Japan. The species in those areas have developed resistance.

It was most foule weather ... and so we went into an alehouse - Samuel Pepys
Offline Devonian  
#9 Posted : 13 June 2019 07:00:00(UTC)
Devonian

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Location: East Dartmoor

Originally Posted by: Caz Go to Quoted Post

Do we really know that for certain though Dev?  The names might be new but do we know such diseases haven’t struck before, possibly under a different name, or no name at all if there was little awareness. We are far more conscious of our environment these days and have better understanding of the science and better means of communicating. 

Ash die back is new to these island as are many other disease, invasive species and the rest - all brought here by humans. Was ADB here in the past? The answer is no and is surely irrelevant to what we know - ash die back has been brought here by humans.

"In a 52-48 referendum this would be unfinished business by a long way"

Nigel Farage, Daily Mirror, 16/5/2016

"I think the mistake the government made - led by Theresa May - from the start was to try and claim that a country that had voted 17 million to leave the EU, 16 million to stay, wanted a 100% Brexit"

Osborne, 22/12/18.

Offline Roger Parsons  
#10 Posted : 13 June 2019 07:13:42(UTC)
Roger Parsons

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Location: Lincolnshire

Originally Posted by: Devonian Go to Quoted Post

Ash die back is new to these island as are many other disease, invasive species and the rest - all brought here by humans. Was ADB here in the past? The answer is no and is surely irrelevant to what we know - ash die back has been brought here by humans.

Quite, Dev - using my earlier model for Chalara Ash Die Back: a brief note...

Agent = Chalara aka Hymenoscyphus fraxineus of eastern Asian origin. Native ash spp apparently resistant.

Host = Ash aka Fraxinus species.

Environment = UK temperate woodland.

Vector = human activity - importation of infected stock and subsequent woodland management and phyto-sanitary measures.

For a thorough account of CADB see:

https://www.forestresearch.gov.uk/tools-and-resources/pest-and-disease-resources/chalara-ash-dieback-hymenoscyphus-fraxineus/

Roger

 

RogerP

West Lindsey district of Lincolnshire

No county (Lincolnshire) has better churches and worse houses. The poorer sort of people wash their clothes with hog's dung, and burn dried cow's dung for want of better fuel; whence comes the Lincolnshire proverb: "Where the hogs shite soap and the cows shite fire".

Curiosities of Great Britain (c.1780)

Online Lionel Hutz  
#11 Posted : 13 June 2019 08:08:04(UTC)
Lionel Hutz

Rank: Advanced Member

Joined: 05/04/2006(UTC)
Posts: 3,485
Man
Ireland

Originally Posted by: DEW Go to Quoted Post

 

If you search 'Elm decline' pollen records show a dramatic drop in the elm population at 4000 BC and again to a lesser extent 1000 BC. Dutch elm disease is suspected but not proved.

Other diseases are not new globally but have arrived here as a result of global trade e.g. phylloxera on vines from US, chalara on ash from Japan. The species in those areas have developed resistance.

Is the correct answer, in my view - at least in most cases. Generally, these diseases are artificially but accidentally imported like this for example https://en.wikipedia.org/wiki/Emerald_ash_borer . He's relatively harmless in his native territory but once he arrives here, he'll make Ash Dieback/Calara look like a picnic.

If you look at the link that Roger posted on the Ash thread, you'll see that most of the diseases mentioned came here artificially(or at least the pests which spread/cause them did) https://www.woodlandtrust.org.uk/visiting-woods/tree-diseases-and-pests/key-threats/

Admittedly, the source of some diseases is unknown https://en.wikipedia.org/wiki/Acute_oak_decline

Remember, these are just some of the headline diseases. There are others out there which are more subtle in their effects like oak mildew https://en.wikipedia.org/wiki/Erysiphe_alphitoides In the past, oak was a tree which could grow in the shade of other trees. However, in the twentieth century, it changed into a light demanding tree which couldn't thrive in shade. The great Oliver Rackham theorised that the cause of this change was oak mildew, a common feature of oak since around 1900. Its origins are uncertain but it does seem to have been introduced to Europe by humans(albeit over a century ago now). So oak mildew probably won't kill many oaks but it will probably cause a substantial reduction in the number of oaks growing in our woods.

Interesting that you mention past probable outbreaks of Dutch Elm disease. Our own modern bout of DED itself came in at least two waves. The first(which I think affected the British Isles in the 1920's and 30's) was less virulent than the current strain which hit in the 70's(though only reaching my location in the late 80's).

Edited by user 13 June 2019 09:01:44(UTC)  | Reason: Not specified

Lionel Hutz

Nr.Waterford , S E Ireland

68m ASL

Offline Northern Sky  
#12 Posted : 13 June 2019 12:00:56(UTC)
Northern Sky

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Joined: 16/08/2010(UTC)
Posts: 3,836
Location: Leeds W Yorks

Hi Lionel, just interested in your statement that oak was once a species which could grow in the shade of other trees. Is that based on the 'closed canopy' view?
Online Lionel Hutz  
#13 Posted : 13 June 2019 13:27:20(UTC)
Lionel Hutz

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Ireland

Originally Posted by: Northern Sky Go to Quoted Post
Hi Lionel, just interested in your statement that oak was once a species which could grow in the shade of other trees. Is that based on the 'closed canopy' view?

I'm not sure exactly what you mean by "closed canopy" view. However, I will try to explain better what I meant. Some species can survive reasonably well in shade e.g. beech, hornbeam, yew, holly. Admittedly , they may often remain below the canopy level and will only really thrive when a large tree dies or falls. However, they will survive as an understory species. However, many other species are light demanding and will not survive at all in shade. I read about this in one of Rackhams books. All I could find through google was this https://www.birdforum.net/showthread.php?t=143130 Not a very academic perhaps but it does quote from Rackham and hopefully explains it a little bit better.

Lionel Hutz

Nr.Waterford , S E Ireland

68m ASL

Offline Northern Sky  
#14 Posted : 13 June 2019 16:16:17(UTC)
Northern Sky

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Joined: 16/08/2010(UTC)
Posts: 3,836
Location: Leeds W Yorks

Originally Posted by: Lionel Hutz Go to Quoted Post

 

I'm not sure exactly what you mean by "closed canopy" view. However, I will try to explain better what I meant. Some species can survive reasonably well in shade e.g. beech, hornbeam, yew, holly. Admittedly , they may often remain below the canopy level and will only really thrive when a large tree dies or falls. However, they will survive as an understory species. However, many other species are light demanding and will not survive at all in shade. I read about this in one of Rackhams books. All I could find through google was this https://www.birdforum.net/showthread.php?t=143130 Not a very academic perhaps but it does quote from Rackham and hopefully explains it a little bit better.

Sorry Lionel perhaps should have explained a bit more. I'm currently reading 'Wilding' about the project at Knepp Farm. I think it was you who recommended it! It's a fantastic book (I'm half way through) and there is a section on oaks and the idea that Britain used to be completely covered in trees - the closed canopy. 

There are records of ancient bog oaks and this supported the idea that oaks grew within that closed canopy and therefore tolerated shade well. However the book talks about how rather than being covered entirely in trees the landscape was much more diverse primarily due to the influence of large herbivores and that oaks actually flourished in areas where tree density was less, meaning of course with more light.

Online Lionel Hutz  
#15 Posted : 13 June 2019 17:03:32(UTC)
Lionel Hutz

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Man
Ireland

Originally Posted by: Northern Sky Go to Quoted Post

 

Sorry Lionel perhaps should have explained a bit more. I'm currently reading 'Wilding' about the project at Knepp Farm. I think it was you who recommended it! It's a fantastic book (I'm half way through) and there is a section on oaks and the idea that Britain used to be completely covered in trees - the closed canopy. 

There are records of ancient bog oaks and this supported the idea that oaks grew within that closed canopy and therefore tolerated shade well. However the book talks about how rather than being covered entirely in trees the landscape was much more diverse primarily due to the influence of large herbivores and that oaks actually flourished in areas where tree density was less, meaning of course with more light.

 I have that book, alright but believe it or not, I haven't got around to reading it yet - it's in my "to read" book pile at the moment! Good to know that it's good - I look forward to reading it.

I had heard of the closed canopy idea before now that you mention it. AFAIK, previously people believed that our landscape was totally forested. However, as you allude to, it's now believed that there were also some open or semi open spaces also, even before we humans got to work on forest clearance. That's interesting about oaks. However, I wouldn't argue with somebody like Oliver Rackham either. Perhaps oaks have gone through this change in behaviour before if your book is correct.

Lionel Hutz

Nr.Waterford , S E Ireland

68m ASL

Offline Roger Parsons  
#16 Posted : 13 June 2019 17:21:53(UTC)
Roger Parsons

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Oliver Rackham would have been pleased that we were giving tree diseases a good discussion. He is famous for saying ‘the Science of Pathology... has been scandalously neglected in Britain". Only last week I was speaking with a naturalist who surveyed the Limewoods here with Rackham.

For some really good quotes which relate closely to this topic, see:

http://britainisnocountr...-country-for-and_43.html

Roger

RogerP

West Lindsey district of Lincolnshire

No county (Lincolnshire) has better churches and worse houses. The poorer sort of people wash their clothes with hog's dung, and burn dried cow's dung for want of better fuel; whence comes the Lincolnshire proverb: "Where the hogs shite soap and the cows shite fire".

Curiosities of Great Britain (c.1780)

Online Lionel Hutz  
#17 Posted : 14 June 2019 08:00:44(UTC)
Lionel Hutz

Rank: Advanced Member

Joined: 05/04/2006(UTC)
Posts: 3,485
Man
Ireland

Originally Posted by: Roger Parsons Go to Quoted Post
Oliver Rackham would have been pleased that we were giving tree diseases a good discussion. He is famous for saying ‘the Science of Pathology... has been scandalously neglected in Britain". Only last week I was speaking with a naturalist who surveyed the Limewoods here with Rackham.
For some really good quotes which relate closely to this topic, see:
http://britainisnocountryforoldmen.blogspot.com/2015/02/britain-is-no-longer-country-for-and_43.html

Roger

A nice piece about Oliver Rackham. Indeed, that whole website is interesting

I have read a couple of his books including "Woodlands". There is so much knowledge packed into his books - the shame is that I seem to remember so little of what I read- a good reason to re-read them, I suppose!

 

Lionel Hutz

Nr.Waterford , S E Ireland

68m ASL

Offline Roger Parsons  
#18 Posted : 14 June 2019 08:07:02(UTC)
Roger Parsons

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I think we need to thank you for starting the thread, Lionel, and Caz too for firing off a couple of cracking questions to stimulate the discussion. Thanks both. Roger
RogerP

West Lindsey district of Lincolnshire

No county (Lincolnshire) has better churches and worse houses. The poorer sort of people wash their clothes with hog's dung, and burn dried cow's dung for want of better fuel; whence comes the Lincolnshire proverb: "Where the hogs shite soap and the cows shite fire".

Curiosities of Great Britain (c.1780)

Online Lionel Hutz  
#19 Posted : 14 June 2019 08:35:46(UTC)
Lionel Hutz

Rank: Advanced Member

Joined: 05/04/2006(UTC)
Posts: 3,485
Man
Ireland

Originally Posted by: Roger Parsons Go to Quoted Post
I think we need to thank you for starting the thread, Lionel, and Caz too for firing off a couple of cracking questions to stimulate the discussion. Thanks both. Roger

Well, to be fair, Devonian started the "Ash" thread, so we should thank him too! By and large, we've got very good people posting here in this forum but (mostly)without the argy-bargy that we sometimes get on UIA.

Lionel Hutz

Nr.Waterford , S E Ireland

68m ASL

Offline DEW  
#20 Posted : 14 June 2019 08:40:47(UTC)
DEW

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Location: Chichester 12m. asl

A local 1950s leafy estate (Summersdale, for those who know Chichester) was planted ot with horse chestnuts which are now mature trees. Five or six years back they were under attack from canker and leaf miner, (and from people who may have had ulterior motives, (big trees generate an awful lot of leaves to clear up) who wanted to fell them.

I'm glad to say the trees are still there and looking very  healthy, with only just some canker scars still visible but you look for them carefully.

It was most foule weather ... and so we went into an alehouse - Samuel Pepys
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