Chalara fraxinea - Your Assistance Please

[apggs]

Good evening,

 

Currently writing an assignment for Y3 of my Arboriculture degree. Interested to gather your thoughts – whatever they may be – on the following statement:

 

“Ash Dieback (Chalara fraxinea) poses a threat to the Ash population in the UK. However;

• it is not the next Dutch Elm Disease;

• it conveniently arrived at a time when the Forestry Commission was facing budget cuts and they convinced the DEFRA that this disease posed enough of a threat to the nations UK Ash population to justify their funding;

• the severity and risk has been dramatised by the press”

 

ANY feedback, arguments or thoughts on the above will be greatly appreciated.

 

This does NOT reflect my personal opinions. They are merely intended to be thought and discussion provoking.

[JLA Arborists]

I don't believe for one second the media will exaggerate the story to sell papers etc lol

[martwizz]

I was thinking the other day about how quickly people stopped talking about it. But these things take time, who knows how serious it really is/was?

 

I had no idea about the speculation on the funding issue, certainly interesting!

 

The media always put a bit of an extreme spin on things - but if it were to be as bad as they proposed, the awareness it brought to the general public was excellent.

[jon bown]

think on this

why will the FC not allow an excemption to felling control for ash trees ?

either its not as bad as they are saying it is or they want their cake and to eat it?

 

The Fc want us to give them all the info and all our support but still want the reins and refuse to empower us.

 

Please everyone don't go getting bent out a shape I am not talking about conservation areas or TPOs I am talking about felling control over 5 cube.

 

I posed this ? to the FC and the reply was no reply.

 

Its the same for larch with Pr

 

enjoy your day folks

[Goaty]

On the control point of it. Movement of ash nursery stock has stopped completely. Its not screened and tested. Just a blanket ban. Yet any Joe public could go up to a dieback ash and get some firewood off it drag it about then use his saw on a healthy one. Whilst I realise foot and mouth in livestock is not perhaps the same commercial threat etc. Look at the military response to that, even though it had glaring errors in its handling.

 

Therefore would it make much difference if ash plants were back on the market. Simply plant lower percentage in woodlands to reduce risk. Increase genetic diversity out there. After all if its only certain environmental factors such as humidity, temperature. Its only akin to an allotment disease such as onion rot or clubroot. Just don't grow the affected plants in the affected locations.

[woodyguy]

Interesting post.

Is is the next DED? Well English elm is a clone (in each locality) so there is very little genetic diversity which makes it incredibly susceptible to disease. Ash however is much more varied and it appears some trees are resistant. But ash doesn't sucker in the same way as elm. So elm continues to exist but not as large trees (few exceptions). So ultimately will recover (as it did in 4000bc). Ash presumably will be largely wiped out but will leave a few larger resistant trees that then become the predominant population. So in 200 years time, we will have lots of ash, just different ash.

 

The political angle is difficult. The sheer denial and delay in any action, meaning that we swung almost instantly from it not being a problem, to being too late to do anything, suggests cock up not conspiracy. Comparisons with F&M are interesting. The countryside was shut down for months, millions were spent on compensation, billions was lost by the tourism industry, untold heartache for farmers destroying herds - all to protect an export meat market worth less than £100m. So yes, politically they're idiots who react to the media in illogical and inappropriate ways. Not sure what that proves though.

[apggs]

Thanks for your thoughts guys.

 

Is a lack of genetic diversity an issue across the UK, irrespective of species? There are, in some cases, hundreds of variations within a species, yet we continue, particularly in urban environments, to plant from the same limited pallet. Therefore, when a pest or disease attacks, it smashes it way through multiple hosts because they're all related to each other.

 

So, as Glynn Percival of Bartlett commented the other day, we need to treat the patient, not the pest/disease/infection.

 

Do we need to mass-fell all of the Ash and plant a different species altogether? Do we fell and replant a different cultivar in the hopes that it will be resistant? Or do we attempt to control Chalara itself, leaving the established trees in place and treat the individual trees?

 

Yes I agree that the media have assisted in highlighting the disease to the general public and there is no doubt that they have blown it up to sell papers, as only the media can. However, is it a result of the FC publishing notices, or did they pick it up first and run with it?

 

Any further comments greatly received.

 

Thanks in advance.

[Paul Jenks]

Whatever the extent of this particular genie, it's out of the bottle. There are a lot of dead and dying ash trees around and some will have seeded and some not. Most will fall to bits without the aid of a climber and chainsaw and will become excellent hosts for all sorts of beasts and bugs.

No amount of sterilising saws or boots will make a difference to the spread across the country in the long run. Whether the FC or the government knew it was on the rampage a long time in advance of the general release of information is currently conjecture. The value to the economy is a debatable point and I would suggest less immediate than that of our meat exporting. From the government statistics, DEFRA, the meat and meat products export trade is worth about £1bn a year, poultry and milk products excluded, + another(£600m).

I doubt ash wood amounts to 100th of that figure and it certainly doesn't employ as many people.

As with many things arboricultural, the timescales for disease transmission in genetically diverse populations are measured in decades so I daresay the issue may have been overplayed by the FC. It's axiomatic that the media has overplayed it, though as this story has a shelf life of many years it's lost its zest for the front page.

I fail to see how a mass fell would solve any perceived problems other than generating a lot of work, hysteria and good firewood. Remove trees when they're stuffed and replant with a suitable replacement.

[apggs]

I agree that the comparisons to meat trade are different, but it was an interesting suggestion on how the media may have handled it.

 

I'm just trying to get to the bottom of whether AD is anywhere as serious as DED, AOD or SOD, or whether it will be a controllable situation within, say, 10 years. Is it going to get to the stage that HC Bleeding Canker has, where it's hard to find a tree that isn't affected?

 

From the point of view of the urban tree manager, thinking of all the liabilities, duties of care, etc, are they better to fell and replant, or build in a shorter inspection cycle and use reaction maintenance, hoping their Ashes last as long as possible?

 

Regarding replanting, what would you consider to be a suitable replacement species? My concern is by replanting, the pallet will get narrower and narrower until we get to an almost The SIMS-like stage: "click here to insert one generic broadleaf tree"; "click here to insert one conical-shaped pine tree"

[agg221]

Regarding replanting, what would you consider to be a suitable replacement species? My concern is by replanting, the pallet will get narrower and narrower until we get to an almost The SIMS-like stage: "click here to insert one generic broadleaf tree"; "click here to insert one conical-shaped pine tree"

 

This I do see as a substantial issue. I think there are three separate scenarios here - urban/suburban, countryside and commercial timber.

 

Taking urban/suburban first, we live in an increasingly risk-averse and litigious society. As has been posted many times before, it is always easier to avoid risk by -not- doing something than by learning enough about a subject to understand the risk thoroughly. From the perspective of the decision maker, this can't always be blamed on laziness. Sometimes it is down to the range of knowledge that an individual is expected to be competent in being excessive, or that they are obliged to rely on external advice which they may not be able to get the confidence in to trust implicitly.

 

This leaves the simplest way of dealing with the question of what to plant being to stick to a very narrow range of 'safe' species. Smaller is safer, avoid things with invasive roots in case someone wants to build there in the future, people don't like trees where 'bits' fall off them (large fruit, large amounts of pollen/blossom etc). Sterile flowering cherries and the odd rowan and willow-leaved pear is about as far as this allows.

 

Countryside - very few people planting so whatever grows stays. With luck, some native species will be successful in out-competing the ubiquitous sycamore.

 

Commercial forestry implies virtual monoculture. Trying to get a return on land which is cost-competitive to harvest against lower labour costs overseas there really isn't a margin for concession to ecology.

 

So overall, ash isn't going to get planted in an urban setting, and it would be a brave person who planted it commercially, so this leaves it dependent on self-sown trees in hedgerows and copses. If the experience with elm is anything to go by, the density of the surviving population will be critical. The problem with elm is that, although there are resistant trees, the very limited genetic diversity means they are a very small proportion and compared with 4000bc the density is much lower (far less tree cover). As such, a surviving tree every few miles means they are not able to pollinate, hence natural preservation of genetic lines becomes very difficult. I have seen large elms removed for reasons which have nothing to do with DED, as you would expect with any species, however the impact with elms is significant. By contrast, if we have the same effect on ash as in Denmark (10% survival) there is a reasonable prospect of retaining trees sufficiently close together to allow fairly rapid recovery relative to the lifespan of a tree, ie the current generation of resistant trees should produce resistant progeny in sufficient numbers to replace those which are killed. If this happens it will be rather bare for one human generation though, and sadly that will be ours.

 

Alec