UKH

The turn to wet and windy weather is seeing a lot of green leaves fall from many of the roadside ash trees here in the north east of England, with sad little crescents of green under each diseased tree at the edge of the road.

I think we’re probably at saturation of spread now and it’s just a case of waiting for the inevitable.  On the up side, I’m thinking of the really healthy ash trees as more likely to be resistant survivors than holdouts now.

There’s plenty of trees in advanced stages with bare branches sticking out  of a central ball of green as latent buds awake.  A fair few of these are overhanging roads, power cables and so on - if they’re not pro actively cleared they’re going to make worse the effects of big winter storms.

In reply to wintertree:

But how many healthy trees are there…chatting to my wife’s cousin recently who manages a 500 acre farm he reckons they will all go…he has been cutting them down for a couple of years now.

Areas of the South Downs where we walk are like a mausoleum with hundreds gone.

In reply to Wimlands:

2 out of 15 ish of ours show no signs of disease.  If been leaving ash saplings to grow wherever they appear, I’m hoping some of those made it but they’ve not done well with this years out-of-order weather.  Looks like several more are going to have to come down this winter.

It’s mostly a roadside thing here as there’s so little established, broad leafed native woodland left.  It’s run riot in Castle Eden Dene where it looks so desperately sad in places now, and some of the new Woodland Trust sites have been hit hard but they’ll recover as they’re mixed planting at quite high density.

In reply to wintertree:

In response to the problem on the farm that I help out on we’re planting trees to help replace the dead Ash.

Planted 5 Elms this year amongst others…might be tempting fate.

In reply to wintertree:

Just reading this…https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/tree-pests-and-di...

Estimates that 80% will die but then goes on to say.

“Initial findings estimate that 1-5% of trees may show reasonable tolerance to ash dieback, but none have been found to display complete resistance.“

In reply to Wimlands:

I wonder how they derived a prediction of 80% attack rate? That corresponds to an R0 value of 5*, but I can't find any supporting reports, though I didn't look too hard tbf. 

* geek alert: assuming random 'contact' between hosts, which of course is incredibly inappropriate for sessile, heterogeneously dispersed organisms and some sort of exponential infection spatial kernel.

In reply to Wimlands:

95% death rate in Denmark and similar in Germany, the wood I've been taking them out from there's maybe three left from several hundred.

In reply to wintertree:

I recall the initial impact a few years ago when it looked like lots of ash trees round here seemed to be affected. The following year seemed to be less severe with some of the initially affected trees appearing to bounce back. You could see the old, dead branches poking through the returning foliage. I'm not sure about this year. I think, perhaps, we are less severely affected here (northern Lancashire) than other areas I've visited? As I walk around here I'm not immediately struck by large numbers of dead-looking trees so that suggests the impact may not be as obvious as a few years ago. Or maybe I've just not been looking closely enough (the value of actually recording hard data instead of 'feelings'!).

In reply to wintertree:

Our understanding is evolving. We should not be felling all trees with signs of the disease unless for public safety. Some are able to bounce back. 

The problem is many managing land think dieback immediately needs a fell and thus are destroying Ash populations that may well otherwise pull through in some form or other.

Brief do's and don't summary here for anyone dealing with trees and somehow learning this for the first time. https://www.devonashdieback.org.uk/take-action/infected-trees-dos-and-donts....

In reply to Wimlands:

This should not have happened.

In reply to A Longleat Boulderer:

When to fell them is a difficult judgement call - leave it too long and if the tree doesn't stabilise then it's rapidly going to become unsafe for climbing, making felling it a lot more expensive.  I'm leaving most of them but a couple have been felled, one for pubic safety and one because it would be really difficult if we let it get past a safe climbing point and it was fast heading that way.  We took the most affected limbs off a third and the remnant is looking pretty good this year.

I am letting all the ash saplings that appear grow where-ever they are (except the one that just won't die right next to the garage wall...) and popping tree protectors on them.    We'll see which if any make it to a decent size and then thin around them.

In reply to wintertree:

To be honest my comment was focussed on woodland management. Not really Ash in a domestic environment.

However on that topic... it's really not hugely more expensive or difficult to use a MEWP than it is to climb an Ash in many domestic settings where the tree must be managed. I don't really climb any Ash at all these days for this reason (among others ... industry guidelines advise against climbing Ash).

In reply to A Longleat Boulderer:

I’ll try and get a decent picture of the downs near us next time I’m walking down there.

it’s a sad sad thing to see with swathes of dead trees. These really do look like they have completely gone with no life left.

My friend is keeping an eye on them on his farm, it’s such a large area he obviously leaves where he can. Like most farmers he has plenty to get on with without going out of his way to find work.

In reply to A Longleat Boulderer:

I can see a shift in rational for managed woodland - we appear to be well beyond the point containment is possible, so culling the infected for disease control makes little sense.

We’re getting in to very site specific details here - but it’s a small patch of land well beyond the domestic plot that’s never been developed for agriculture and that has various constraints making for very poor vehicle access, especially at the preferable time of year for tree surgery.  The cost of getting a crane in there would be significant and it wouldn’t be without knock on damage.

> among others ... industry guidelines advise against climbing Ash).

… which will only get worse with dieback.  Hence jumping the gun whilst the tree surgeon was happy to climb the trunk section.  Always amazes me that people can happily manage the risk of climbing a tree with a chainsaw!  

In reply to wintertree:

I've actually seen the fruiting bodies of chalara fungus on fallen ash leaves and stems, which go on to produce airborne spores if the are left there. Maybe careful clearing and disposing leaf litter (burning or covered composting) from under ash trees in autumn and winter might help to minimise the spread of dieback?

Obviously that would be impractical in all but smaller stands and woodlands, but if younger ash saplings are being encouraged to grow, leaf litter clearance would be an important part of the management plan because they are more susceptible to infection.

https://www.forestresearch.gov.uk/tools-and-resources/fthr/pest-and-disease....

In reply to AllanMac:

Lot of possiblies and mays in that document! Experience here in Germany where the problem took off twenty years ago and all kinds of quarantine meaures were tried initially showed nothing works and felling all the ash trees while a resistant variety is developed is the only way to do it. Particularly in commercial woodlands where you are just wasting money as the timber value is deteriorating without regeneration.

We notified the forestry ministry when it appeared and they patiently marked affected trees, we felled them, they marked some more, felled them and so-on until the authorities gave up and ordered clear felling and replanting with something else. It's no longer notifiable.

Curiously the ones in my garden are still healthy even though they are only a hundred yards from the forest but I don't hold out much hope!

In reply to wintertree:

Dead trees have lots of life  and use!!!  

Some specialist insects & one  species of worm are generally only found in dead/dying trees and the decaying tree will provide plenty of nesting opportunities for  birds such as woodpeckers, nuthatches and so on, who often find the decayed wood ideal.

Unless there is a safety issue then I'd not bother remove them.  According to Oliver Rackhan, (Woodlands, 2006), more damage to the natural environment was caused following the tidying up and clearing following the great storm of 1987? which felled thousands of trees in the South East.

In reply to Billhook:

Most are adjacent to a PROW unfortunately. 

I’ve left some other trees in to rot in safer places that expired in storm Desmond a few years back.  Since we had a grass fire get within a few hundred meters last summer I’m starting to wonder if that’s really wise.

Fascinating little micro environments around here - several places where the whole row of trees along a northern edge of spruce plantation have been toppled lifting up a line of roots up to 100 m long, no interest in clearing them up so there’re new sheltered, dark patches for things to inhabit, as well as the decomposing wood. 

In reply to jimtitt:

The possibles and mays indicate how little is known about ADB. Germany's policy of clear felling of contiguous ash stands and replacing with other species is likely the way to go, at least until we know more about ADB and the genome of possible resistant strains.

The ash genome has very high diversity and it is likely that a resistant phenotype amongst some 'mother trees' will be found from which to propagate. The downside to that is the genomic diversity-narrowing that is likely to take place as a result, weakening resistance in new ash trees to other, as yet unknown, pathogens.

A bit tldr, but there's some good info about ADB here:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6887550/ 

In reply to wintertree:

Pubic safety is very important. Well done for tackling the issue 😜

In reply to wintertree:

I thought Ash Daibach was a far right US politician who got sidelined when the Mango Moron took over.