Threat to the ash tree

[umslopogaas]

Lateral Thinking, I cant give a steer myself on the proportion of ash in the forest flora, but the Woodland Trust probably can, try googling them.

Come to think of it, I used to have (but no longer) a copy of the 'Atlas of the British Flora', which showed the distribution of every species as dots on a map, each dot corresponding to a 10 km square. That should show you the presence of ash on the Downs, though not the abundance.

[umslopogaas]

Lat, re. recovery time after the first wave, we need some more information. The Dutch Elm example is a special case because the insect vector (a bark beetle) flies quite high, so for about twenty years the recovering elms are too small to be detected. In the ash case the disease is wind borne, so in principle any age of tree can be affected. The time taken to recover will, I think, depend mainly on the proportion of resistant trees that survive, and the strength of that resistance. So, guessing wildly, if the disease spreads through the country over the next ten years, survivors will take another five to ten years to recover. Perhaps in twenty years we will see ash coming back into view. But please dont quote me, I know nothing of the rate of disease spread, for one thing.

[jean]

Yes, there is a risk of import on infected trees, and it would be sensible to ban such imports, because for heaven's sake we have enough native ash of our own, they come up like weeds in my garden...

Thank you for such a well-informed post - and yes, this is the bit I can't understand, because ash trees seed almost as readily as sycamores - my allotment would be a forest of them if I didn't get them first.

[Pabmusic]

I realise that we are all concerned about the fate of the ash (and the eco-system of which it's a part), but isn't this the sort of thing we will have to get used to as the temperature of Northern Europe increases? Our climate will warm, we are told, towards a more 'Mediterranean' one; that means that many of the things that make our landscape familiar will die off - often by contracting unfamiliar diseases - oak trees (and many other trees), daffodils, bluebells, apples, blackberries, and so many more. Presumably they will grow much further north (the Hebrides, perhaps?) and our descendants will become used to olives, oranges and bougainvillea.

Not that this outbreak is necessarily connected, though it may be - slight changes in the balance give rise to new selection pressures.

[Richard Tarleton]

However, carping about a perceived (by some) lack of government response since the discovery of infected saplings in February is, I feel, effectively a diversion from encouraging further measures now.

Bryn, the problem and its potential were recognised three years ago. It's reasonable to analyse the decision-making process, or lack of one, in the hope that this might speed up the response to future bio-crises.

[Bryn]

Bryn, the problem and its potential were recognised three years ago. It's reasonable to analyse the decision-making process, or lack of one, in the hope that this might speed up the response to future bio-crises.

I would urge those concerned to read that article linked to above. The whole article, that is, not just the headline or first few paragraphs.

[Resurrection Man]

Spot on, RT. We've managed our paddock to encourage tree growth and so far we have five small oaks and one sycamore and one walnut (grey squirrels have at least one saving grace). All self-seeded.

[Serial_Apologist]

Edit: the chief beneficiary may well turn out to be sycamore, a tree which establishes itself without any help from anybody and against which many foresters and conservationists have an irrational prejudice. It has a lot to be said in its favour.

The problem surely with advocacy for the sycamore is, being compared with oak and ash a relatively recent incomer, its small number of associated species.

[Richard Tarleton]

The problem surely with advocacy for the sycamore is, being compared with oak and ash a relatively recent incomer, its small number of associated species.

Recent-ish - about 500 years, as opposed to before the last glaciation. It's arguable how native beech is in some parts of the country where it is now established. Against sycamore - relatively low number of associated insect species, compared to oak, form does not lend itself to smaller tree-nesting bird species. For: high biomass of some insects, e.g. aphids, making it a favourite with canopy feeding woodland birds (eg chiffchaff and many more). Base-rich bark makes it excellent for lichens (cf beech). It comes into leaf early (unlike ash, to the latter's disadvantage) casting a denser shade which favours ground flora that flower early (primroses, bluebells, wood anemones), and shade-tolerant communities such as our lovely fern communities here in Wales. It is about the only tree, apart from hawthorn and blackthorn, which does well in westerly maritime conditions eg along our coast here. As Pab has reminded us there is a constant process of Darwinian evolution at work. The longer it stays, the more species will make use of it.

It's been here a lot longer than nearly all of the conifers that we see around us as well as some of our woodland mammal species and we may be approaching a time when it is no longer sensible to be sniffy about it.

[vinteuil]

there is a constant process of Darwinian evolution at work. / ... /

we may be approaching a time when it is no longer sensible to be sniffy about it.

The bl***y sycamore is certainly a thriving survivor.

I have to remove several dozen seedlings every year from my tiny London pocket-handkerchief of a garden.

I'm sure that when everything else on this planet is destroyed by nuclear holocaust or other human stupidity, the sycamore and the cockroach will happily continue...

the sort of thing we will have to get used to as the temperature of Northern Europe increases? Our climate will warm, we are told, towards a more 'Mediterranean' one; that means that many of the things that make our landscape familiar will die off - often by contracting unfamiliar diseases - oak trees (and many other trees), daffodils, bluebells, apples, blackberries, and so many more. Presumably they will grow much further north (the Hebrides, perhaps?) and our descendants will become used to olives, oranges and bougainvillea.

:

... I wish I shared Pabmusic's sunny optimism - his prospect is most attractive. Sadly I suscribe to the more depressing alternative - that global warming and consequent melting of Greenland and Arctic icecaps will lead to disturbance of Atlantic currents - specifically the North Atlantic Drift / Gulf Stream - so that the British Isles will lose their earlier benign climate and return to a more Canadian cold, as befits our latitude...

[ahinton]

... I wish I shared Pabmusic's sunny optimism - his prospect is most attractive. Sadly I suscribe to the more depressing alternative - that global warming and consequent melting of Greenland and Arctic icecaps will lead to disturbance of Atlantic currents - specifically the North Atlantic Drift / Gulf Stream - so that the British Isles will lose their earlier benign climate and return to a more Canadian cold, as befits our latitude...

I suppose that it might, although I don;t see that anything in particular "befits our latitude" and, in any case, if that does happen, i hope to have gone south well beforehand, because I couldn't stand that.

[Lateralthinking1]

Lateral Thinking, I cant give a steer myself on the proportion of ash in the forest flora, but the Woodland Trust probably can, try googling them.

Come to think of it, I used to have (but no longer) a copy of the 'Atlas of the British Flora', which showed the distribution of every species as dots on a map, each dot corresponding to a 10 km square. That should show you the presence of ash on the Downs, though not the abundance.

umslopogaas

Many thanks for your reply and also for your reply in post 32. I will have a look at the Woodland Trust website as you suggest.

[Simon]

although I don't see that anything in particular "befits our latitude"

He means "as one might expect, given our latitude, if it didn't have other factors influencing it such as the GS."

[gradus]

It seems very unlikely, as is the case, that any government would care enough to act on scientific evidence about a tree disease before the disease shows itself here. I didn't see anything in the public domain from the Forestry Commission/RHS or anyone else with expert knowledge before the current furore, odd omission as it is so serious. At least the problem is now recognised and we can report it (http://www.dailymail.co.uk/sciencete...-Ash-trees.htm) lf we see it before leaf fall is over.
Did somebody day that the wood from diseased trees can't be burnt because the spores would be spread by the smoke? Is this scientifically correct as it would compound the problem if we couldn't even burn the wood - Ash being the best of all for the purpose.

[Pabmusic]

... I wish I shared Pabmusic's sunny optimism - his prospect is most attractive. Sadly I suscribe to the more depressing alternative - that global warming and consequent melting of Greenland and Arctic icecaps will lead to disturbance of Atlantic currents - specifically the North Atlantic Drift / Gulf Stream - so that the British Isles will lose their earlier benign climate and return to a more Canadian cold, as befits our latitude...

I wish I shared my optimism, too, for changes in the Gulf Stream are quite possible.