Chalara fraxinea - die back of ash, in situ

[David Humphries]

I had the opportunity to get out into one of the confirmed sites today with the Forestry Commision.

 

The FC and others, have put together a lot of really clear and useful data on the spread & symptoms of the disease,

 

FC Link

 

but I felt that I needed to have a look at a site in the flesh to get a feel for what is being affected and how it might be spreading

 

The site is a privately owned wood that is mainly standard & coppice with a few fine pollards and a stand of timber crop, the species ranging predominantly through oak, field maple, hazel, elm (regen) & ash.

 

The wood is isolated within arable farm land and sits fairly high within its surrounding landscape.

 

There is one main ride running roughly east/west.

 

 

 

My appreciation to the FC at Santon Downham (and land owner) for facilitating the impromptu site visit, especially during the obvious busy time with the rapid survey just being finalised.

 

I shall be taking back what I learnt to a meeting at work tomorrow to share & inform those who will be looking out for the progress of this disease into the urban environment.

 

 

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[David Humphries]

The recent survey of this wood involved a rapid walk over of the perimeter & main rides & paths.

 

Currently the only types of ash in this wood that appear to be infected are young 2-3m (5-10 year old) natural regeneration at the edge of the main ride.

None of the older saplings, young or mature trees appear to be affected at this time.

 

The map shows roughly where the saplings (we witnissed with the symptoms) were within the wood.

 

 

 

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[David Humphries]

I didn't get a chance to study the site for long to get a good look for any fruiting bodies on the discarded rachises (leaf stalks).

But most of the associated symptoms were in evidence.

Wilted small branches, necrotic leaf stalks, bark lesions along where the side branchlets were affected etc....

 

Worth bearing in mind that the fall doesn't help with spotting the subtle differences between a healthy shutting down tree & one with the disease.

 

I will get together a gallery of these shots and when/if I manage get any of the fruit bodies, in to the Arbtalk fungi directory.

 

 

 

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[HCR]

What biosecurity measures were in place?

 

Interesting about it only being on younger trees.

[David Humphries]

Subtle differences need to be considered like here, where the central original shoots of these two small branches have possibly been frosted and then taken over by the auxilary buds, rather than the necrosis of Chalara.

 

 

 

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[David Humphries]

What biosecurity measures were in place?

 

Interesting about it only being on younger trees.

 

Knocking out residual mud from tread of boots, then application of Propellar for foot wear, change of clothes & boots, then I made sure the car was washed (specifically the wheel treads & arches), as I'm going back down to London tomorrow and mindful not to spread anything I shouldn't be.

 

I felt that the above was ample,

especially as this is wind bourne and going to be eventually everwhere.

 

 

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[HCR]

It took me a while to work out what that bottom picture was!

 

 

 

 

 

 

 

 

 

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[Ben Ballard]

Good post David can lesions be found on stems and branches with out the dieback in tips first ?

[David Humphries]

Good post David can lesions be found on stems and branches with out the dieback in tips first ?

 

I don't think so Ben,

 

the infection moves along the rachis (leaf stalk) past the union and into (up & down) the branch.

 

 

 

 

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[Ben Ballard]

Could this be it was the snapped out top of a 10 year old ash? Any help would be great thanks Ben