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Ash disease - some hope

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Ash disease - some hope

Postby Stephen1 » Mon Nov 05, 2012 9:36 pm

There is some good evidence that some individuals demonstrate a good level of resistance to the disease and that this resistance is heritable. There is also some reasonably good evidence that this resitance is related to the time of leaf fall. Those of you with a good number of Ash in your woodlands will probably have noticed that some individuals will have lost all their leaves before some other trees have shed many at all. It seems that what the trees showing resistance have in common is that they are all trees that shed their leaves early.

I think it's now very unlikely that this disease can be contained, let alone erradicated in the U.K., and I think it unlikely, based on the pattern of spread in Europe, that it will take much longer than a decade or so for the majority of our ash trees to become infected. It might be interesting - and potentially useful in helping develop particularly resistant strains to breed from and repopulate ash into our woodlands - to mark those ash trees on your land which lost their leaves early now.

There is a poorly tested hypothesis about why those trees that their shed leaves early might have a higher resistance - if anyone's interested just ask - but it is really only a suggestion as to the cause of the link and whether it's right or wrong doesn't detract from the pattern of resistance being associated with early leaf drop. Now is the best time of year to reccord the differences in leaf drop on your trees - perhaps if you're doing any thinning and you have to choose between ash trees, it would be worth knowing if one was a particularly early leaf dropper and thin to favour that one.
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Re: Ash disease - some hope

Postby paulorna » Mon Nov 05, 2012 10:19 pm

hi stephan1.. i am about a week away from signing the dotted line on a woodland in kent that holds about 30/40% ash... on hearing the news about this disease over the last week or so. i am absolutely gutted as they are such a lovely tree with herritage and purpose.. was one of the reasons i fell in love with the woodland in first place...not sure wot to do now, gonna be spending a lot of money and then to find they die or i have to get them felled which will cost a fortune, and then having to replace them !! spoke to the forestry commission to find out who would foot the bill, and they couldnt give straight answer but suggested it would be the land owner. also she was honest in saying that as we are only a small woodland (8.5ac) and were not a national grower business, that we wouldnt recieve much help in any case..except a grant for replanting..i am almost certain that the ash there are not infected ( yet ) . after your info i now need to visit site to mark which are the early dropers.. but actually i not sure wether i should go ahead with the purchase !! what'd ya think ? paul
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Re: Ash disease - some hope

Postby Alex » Tue Nov 06, 2012 9:49 am

http://www.telegraph.co.uk/earth/965259 ... d-ash.html

Interesting article here, about resistance and the views on ways of tackling it.

Good luck Paul, I'd personally go for it, and the make the most out of it, heck you might have some very resistant trees!
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Re: Ash disease - some hope

Postby coppiceer » Tue Nov 06, 2012 1:45 pm

That's very encouraging Stephen1. As a matter of interest, just before I rush out and take heel-cuttings from appropriate specimens, do you have any references for this that I could quote from the tree-tops?
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Re: Ash disease - some hope

Postby Stephen1 » Tue Nov 06, 2012 2:17 pm

coppiceer wrote:That's very encouraging Stephen1. As a matter of interest, just before I rush out and take heel-cuttings from appropriate specimens, do you have any references for this that I could quote from the tree-tops?


Hi Coppiceer

Please don't think I'm being patronizing by saying that probably the clearest paper for the layman is;

Mckinney et al. in Heredity 2011 106(5) p 788-797
"Presence of natural genetic resistance in Fraxinus Excelsior to Chalara Fraxinea."

(skip to the paragraph under - "Effect of phenology on susceptibility" if you're in a hurry!)

I'm not suggesting you're a layman, or in any way non-expert (Or suggesting that I am an expert!) but some of the more mycology oriented papers are a bit jargon dense if you're not familiar with the terms.

Essentially though I intend to do as you suggest, either heel-cuttings this autumn which do reasonably well with ash, but also I'll mark the trees that drop their leaves early this autumn and then next spring I'll treat etiolated shoots from them with rooting hormone (IBA). (I'll cut down some <10 year old early leaf droppers - let them start to coppice back up - when the shoots reach about 4 inches I'll cover them with a large dark bucket to exclude the light - these shoots will then very rapidly extend in the dark - once they're about 8 inches long I'll cut them, treat them with IBA and set them in pots to root covered with clear bags to prevent them from desicating until hardened off. This method has a very high take rate - if managed well you can expect a 90% + take rate.

If you only have larger trees that drop late - you can cut a branch and once it starts to produce shoots just concoct a way of getting them to grow in the dark for a while with buckets, duck tape and black drain pipes etc.

Hope I'm not trying to teach you to suck eggs!
Good luck
Stephen
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Re: Ash disease - some hope

Postby Stephen1 » Tue Nov 06, 2012 2:32 pm

Just to add;

Early leaf loss may aid in preventing infection into the twigs/stems/trunk of the trees, but there will also be other traits that affect how the tree's biochemistry intereacts with the fungus once infection into the stems of the tree has occured. As yet little is know about the biochemistry involved, or the level of genetic variation within ash - however it is to be expected that there will be less variation in the native british population than the continental populations. (As effectively a small subset of the european population recolonised britain after the last ice age - yes there are aguments about refugia populations of ash in the far SW of Britain -but I'm not convinced).

I've been pretty casual with my use of language - ultimately it's important not to confuse susceptibility with true resistance.
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Re: Ash disease - some hope

Postby Stephen1 » Tue Nov 06, 2012 3:29 pm

Hi Paul

There will be two phases to dealing with the infection. At the moment the F.C. is still clinging to a hope that it can either eliminate or at least control the area of the UK where the disease becomes endemic. It is very unlikely that this strategy will work, but it is worth a try. Whilst this strategy persists then wherever the disease is found land owners will have to destroy their trees and foot the bill themselves - the F.C. will help with the cost of restocking but not with the cost of felling or burning.

Once the attempt to eliminate/control is perceived as having failed then the obligation to destroy trees where the disease occurs will be relaxed. You will be allowed to let the trees die naturally and remain as standing and fallen dead wood within the woodland. You will only have to pay for making them safe if they are near a road or public right of way.

There will be many ecological pros and cons (although there is no question the cons outweigh the pros)- and five years down the line a wood such as the one you describe will be visually attractive again as a mosaic of young trees of other species regenerating (if you control the deer) and large standing dead wood - the woodpecker populations will massively increase (as they did following the initial spread of Dutch Elm disease in the 1970s) - The woodland won't feel dead it will be very much alive.

You say ash makes up 30-40% of the trees - are you really sure it's as large a proportion as that? Which other species of trees are present in large numbers? If you give me an idea of the species present and their size structure then we could speculate on how the wood might develop following the death of the ash. Perhaps that might help you decide? (of course this would assume the disease doesn't strike until after the obligtion to fell and burn has been lifted)

My gut feeling is that if you feel attracted to that wood - then you're resonance with the place is with more than just the prescence of Ash - if you have the financial buffer that could allow you to deal with the worse case scenario of the wood becoming infected next year then go for it. I think it very unlikely that you will be obliged to destroy all the ash if infection hasn't reached you by 2014.

If I were you though, and the proportion of ash trees really is as high as 40%, then I would attempt to negotiate with the seller. Nobody with an interest in buying woodland will have failed to have heard about this problem. I think it is reasonable to assume that ash woodlands are significantly less desirable (in the sense that many potential buyers will be put off now) than they were a few months ago. I think you should make this point to the seller and either push for a significant reduction in the price or get them to indemnify you against a proportion of the cost you might incur if you become obliged to fell the ash trees. The seller knows the problem, they know ash woodlnad has just become harder to sell, and the longer they hold on to it the greater the risk that they will have to foot the bill to destroy the ash trees if they become infected. I think it would be reasonable to agree with them that they pay 50% of any of the cost arising out of the disease within 5 years of ownership. (I would only attempt to do this if ash really is more than 20% of the canopy trees of this woodland though - go back and do a true systematic assessment not just a rough guess!)

Good Luck!
Last edited by Stephen1 on Tue Nov 06, 2012 4:52 pm, edited 1 time in total.
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Re: Ash disease - some hope

Postby Alex » Tue Nov 06, 2012 3:34 pm

oldclaypaws wrote:
Alex wrote:http://www.telegraph.co.uk/earth/9652599/Trees-that-thrive-amid-killer-fungus-hold-secret-to-saving-threatened-ash.html

Interesting article here, about resistance and the views on ways of tackling it.

Good luck Paul, I'd personally go for it, and the make the most out of it, heck you might have some very resistant trees!


On November 3rd under 'Ash Chalara Fungus spreads' I posted this message;

Informative and hopeful article here which offers a perspective from countries that are now experienced in the disease and its long term impact.

http://www.telegraph.co.uk/earth/965259 ... d-ash.html

I trust I should take plagiarism as a form of flattery, or maybe I should post in bigger bolder typeface? :roll:



:oops:

My bad, I didn't just copy your post though! We must just read the same articles, and there's no harm in posting a link here too.

Great financial advice from Stephen.
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Re: Ash disease - some hope

Postby paulorna » Tue Nov 06, 2012 10:58 pm

stephen1.. thanx very much for the enlightenment.. i will heed to your advice.. and report back to you.. regards paul
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Re: Ash disease - some hope

Postby docsquid » Thu Nov 08, 2012 2:22 pm

Posted in another thread, but relevant here - a very good summary of potential silvicultural strategies for infected stands of ash.
http://bfw.ac.at/400/pdf/fsaktuell_55_6.pdf
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