Ash die back

[Mark J]

I was out surveying this week and came across this mature ash. It's the first time that I've seen advanced symptoms on primary and secondary branches on a mature tree.

 

[Stere]

Thats pretty mild syptoms compared with alot of trees in North Wales, seem your are a year behind in the progression  of it compared to here.

 

 

[The avantgardener]

This is what we are coming across in East Sussex although it is pretty extensive all over the South East.

[Peasgood]

4 hours ago, The avantgardener said:

This is what we are coming across in East Sussex although it is pretty extensive all over the South East.

 

Is all that is wrong with the tree caused by chalara ? Including the internal rot

[The avantgardener]

6 hours ago, Peasgood said:

Is all that is wrong with the tree caused by chalara ? Including the internal rot

The total dieback of the crown is caused by Chalara, the weakened tree has then succumbed to another pathogen which has caused butt decay and/or death of the Cambium layer.

[Gary Prentice]

5 hours ago, The avantgardener said:

The total dieback of the crown is caused by Chalara, the weakened tree has then succumbed to another pathogen which has caused butt decay and/or death of the Cambium layer.

But there does seem to be, or it's being suggested that there is, some link between Chalara and colonisation by other pathogens. Whether Chalara in basal shoots opens the door to other fungi or what is still being debated atm. There's lots of reports of trees with only slight foliage colonisation that are really unsound due to unexpected basal delay. 

[JSN]

It’s all a bit chicken and egg, isn’t it? Whose to say which is the primary / secondary pathogen.  To me it seems plausible that the basal decay was there first - held in check by compartmentalisation, supported by a healthy crown, and then Chalara infects the vascular system - weakening / killing off the crown - allowing the basal decay unhindered access to the rest of the stem.  

It’s highly likely to be a complex web of factors. 

[The avantgardener]

I would estimate that at least fifty percent of the 500 plus Ash trees that we thinned in this compartment showed some form of internal decay at the base, even if the crown was showing only slight die back symptoms. Most of the trees had the buttresses left on as a hold when felling, the the hinge wood was weak or decayed. The tree survey completed the previous Autumn had highlighted large amounts of honey fungus present in the stand.

We will be removing a similar amount in another stand this year.

[mitchel]

i feel like everyones desperate for it to be the next dutch elm disease but no authority's seem to want to take on tackling it due to the cost. 

[Gary Prentice]

7 hours ago, mitchel said:

feel like everyones desperate for it to be the next dutch elm disease

How do you mean?

 

It's worse IMO. Although they're very similar in the way they affect the tree, at least with DED  the vector was a little less effective. The Elm bark beetle had a limited capability of flight whereas  Hymenoscyphus, being airborne, spreads much more quickly (it's covered the best part of the country within 15 yrs).

Also ash are becoming much more hazardous than, I think, expected. In 2014 European reports were that mature trees might live with and survive for up to a decade (as some elms seemed to) but the brittleness of ash dead would is alarming. 

 

Everything needs to change. Talking to my LA at the beginning of the summer I was told that, for 'Highway Inspections' they were zoning roads, inspecting busier/faster routes every year or two while quiet residential streets might only be zoned for five yearly inspection. I asked if they thought it was reasonable to just look at ash every fives?  I met the head of arb a week or two back, another matter, and he asked that I report any sightings - or either their infected trees or those in private hands that could affect the highway. 

 

The costs just keep adding up. Work can't be delayed because of the rapidity with which they are dying back, so they're high priority. Private trees close to roads have to be served notices to deal with them, then re-inspected to check whether they have been removed/made safe, more and more officer time and costs, and on top of everything how do you deal with the sudden volumes of timber and chip that are expected? It's not like your teams are going to be picking up a couple of trunks a week, it's going to be street after street of them. And that's before you look at ash trees in schools and parks. 

 

The TO prepared a report for the finance department, back in 2014, estimating that, based on the numbers of roadside ash and areas of high occupation, the arb department might need a million quid a year (for ten years) to deal with die-back. Based on their known ash stock and at an average cost of £300-350 per tree, to fell, grind and replant. 

 

I imagine hat the thinking, back then, was that there would be a relatively linear progression in the spread of the disease and it could be dealt with steady away over a number of years. Las year we were just starting to see it in small trees. In a few mature trees we had unconfirmed suspicions of infection. This year it's almost everywhere you look! In some trees it's advanced so quickly that I wonder how it was missed last summer (these are trees I pass almost weekly). Thing is, I don't think that it was missed, I think that it's spreading through both individual trees and the population as a whole at an unbelievable rate - far quicker than expected based on European experience and reporting. We were simply unprepared. 

 

Look online and see what LAs are publishing to advise the public, there is very little. Most of what is was written five years ago, when it wasn't reported how quickly hey were becoming hazardous, no one that I've met locally this summer has much consciousness about it, it's just a disease that got some press coverage years ago. 

This is a tree that I pass every day, last summer there were not observable symptoms!

 

 

 

Edited September 28, 2019 by Gary Prentice