Ash dieback at Ditchling Beacon

Ash dieback on a mature tree

Many of our young trees on and around Ditchling Beacon are ash (Fraxinus excelsior) and as a result many of them will probably be lost to this fungal disease over the next 10 years. The effects are already clearly visible in the tops of the trees at Ditchling and ash dieback will certainly change the landscape considerably over time.

Ash dieback is a growing concern across the country including on the South Downs here in Sussex. This fungal disease is changing our local habitats and we are working hard to lessen its effects.  As always we will be working to try to make sure that this transition is as smooth as possible in our key habitats. We want to ensure that it has as little impact as possible on the wildlife and wild flowers in the area during this time.  However, due to the sheer scale of the issue, we have already been planning for the potential effects of this widespread disease on Ditchling and our other properties and have built this into our practical tasks and property plans across the whole South Downs.

What you can see at Harting now?

The effects on a young ash tree are most noticeable as this disease enters the tree through the leaves and so affects the tips of the branches first. It then works its way down the tree towards the roots so small trees die more quickly.

A close up showing the effects of ash dieback
The effects of ash dieback
A close up showing the effects of ash dieback

The effect on larger trees is still noticeable if you take a closer look. The tips of the tree will have dead twigs sticking out of the canopy and in man cases over 50% of the canopy is ;already dead. The length of these dead twigs is an indication of how many years ago the tree was infected. Ditchling was one of the sites hit this year by the fungus arriving in this country so has a lot of mature trees with substantial dieback.  In August to October you may see twigs with retained drooping black leaves. These drooping leaves indicate the twigs affected this season as part of the spread of ash dieback, and next season those twigs won’t grow a leaf at all.

What about long term?

This action of dying back over the seasons means that the fungus will keep moving along the branches, back down away from the tip towards the heart of the tree until it has killed off all the living ash tissue in the tree.  In Poland, where the fungus arrived in 1992, it has been well studied and documented. There and in other European countries there appears to be a proportion of ash stock that is resistant to the disease.  It is assumed this will also be the case in this county so we are looking and watching to see if any of the ash trees on Ditchling match this situation. Hopefully any tree that is resistant will shed seed that is resistant and we will be able to regrow ash from that stock. It is totally unaffected trees we are looking for; any tree that is showing signs will progressively die back and can reasonably be assumed to have no resistance.  We will continue to clear many of these affected trees but trees that look clear of the disease will not be felled and may well in the future be used as seed trees to help recolonise other woodland areas.

Frequently asked questions

What are you doing on Hill Lane?

Hill Lane will be closed from the 15 - 19 October 2019. We are working with  forestry contractors to remove all the ash trees that are within striking distance of the road to protect all users of this route.  

Is there nothing you can do to stop the trees getting the disease?

No, the disease is airborne. For individual trees you could mulch the roots and remove any dead and dying limbs to prevent hazard.  In low density situations (parks and gardens) infected trees and fallen leaves can be removed to prevent further infection, but in a woodland setting this is not possible.

Why do you have to close the road?

The road is closed for public safety as well as for our contractors safety. Our contractors can complete the job quickly and efficiently if uninterrupted.

Won’t the ash trees just grow up again?

Ash trees seed heavily and coppice (regenerate from cut stems) successfully so we do expect small trees to start to develop. However, evidence has shown that younger and coppiced trees are more vulnerable to the disease, so it is unlikely that they will survive beyond a couple of years.  We hope that other tree species will take advantage of the light and repopulate these areas given time.

What if one of the trees cut down was one of the small percentage that will be resistant to ash die back?

There is a chance that we may cut down a tree that would have been resistant to the disease, however we can’t take the chance. Evidence from Europe has shown that some trees will show signs of the disease but eventually will pull through.  It will take too long to determine which trees are resistant, and would put people’s safety at risk to wait. The work will only entail the removal of ash trees within striking distance of the road.  All other ash trees will be left throughout our woodlands, to determine naturally whether they have resistance or to provide important dead wood habitat.

Will there be more work here like this in the future?

At present we are prioritising ash tree removal near roads, car parks, popular muster points, busy public rights of way and buildings.The Ranger team began conducting systematic surveys of the ash trees in June 2018 and will continue to do so for the next 10 years.

Will you be planting trees to replace the ones you have removed?

Initially no. We have agreed with the Forestry Commission that wWe will leave the area to naturally regenerate from the local seed source of the surrounding trees, which has proven a more resilient way for a woodlandhabitats to develop.  

We are following advice from the Forestry Commission and are only carrying out the work with people’s safety in mind. It is sad that we are having to do the work at all, and as a team we are going to mourn the loss of ash trees across the South Downs as the diseases progresses, but we need to take action at this time and in this location. Some trees will survive and provide the seed source for ash to recover and become as prolific in our woodlands as they are today for future generations, we must take heart in that.  For more detailed information about the disease please visit the Forestry Commission website.