The trees have been infected with the disease known as ash dieback.

The most recent disease, ash dieback, is now on 155 sites around Britain.

Once a tree has ash dieback there is little that can be done and it could take up to ten years to die.

Ash dieback has now been identified at 16 sites across Wales.

There is no cure for ash dieback but some trees have already shown resistance.

Earlier this week industry, conservation groups and scientists met for a summit on how to deal with ash dieback.

The public are being asked to help in the fight against ash dieback by playing a computer game that analyses genetic data on the disease.

He said a number of “highly suspect” sites in Kent were expected to be confirmed as having ash dieback today.

Scotland currently has 111 recorded ash dieback cases among its 10.7 million trees.

These days you can crunch data on cancer or monitor the spread of ash dieback while playing a simple computer game.

This was tested and updated during the height of the ash dieback crisis.

Ash dieback: What will be rising from the ashes?

This data will help those scientists aiming to understand and ultimately limit the impact of ash dieback.

Is it too late to stop ash dieback?

"If a mature tree gets ash dieback there no point in chopping it down," he said.

Encouraging the public and landowners to help monitor trees for signs of ash dieback.

Scientists have proposed a radical solution to help trees develop resistance to ash dieback.

Ash dieback came to Britain via two different routes.

Ash dieback has highlighted the risks of diseases being brought over with the imported trees.

Dead leaves on a tree afflicted by ash dieback in Ipswich.

She added: "Hopefully, ash dieback will make people realise just how precious and valuable trees are."

Ash dieback will not be the last imported disease to endanger the British countryside.

Cases of ash dieback have been found in Kent and Essex.

Ash dieback has had a lot of press, but there is also leaf miner and sudden oak death.

Ash dieback is originally thought to have come into Europe from Japan on imports.

An ash tree infected with Chalara dieback near Framlingham, south-east England.

The ash tree has "seeded prolifically," which is a good sign given the threat from the Chalara dieback disease threatening woodland habitats.

Until now the Chalara dieback in Wales had been confined to newly planted sites in trees from nurseries known to hold infected stock.

Chalara dieback of ash (Chalara fraxinea)

These include red band needle blight in pines, bleeding chestnut canker, chalara dieback of ash and Phytophthora ramorum, a fungus which kills larch, among many other plants.

The Woodland Trust is calling for a mandatory ban on the import of ash trees from outside the UK to stop Chalara dieback of ash becoming established here.

Chalara dieback of ash, caused by the fungus chalara fraxinea, was identified at the new Welsh sites during a "trace forward" inspection of young trees sourced from known infected nurseries.

The Chalara fraxinea fungus, which causes a disease called Chalara dieback, was first found in ash trees in a nursery in Buckinghamshire in February, The Daily Telegraph reported.

The survey includes a guide to six of the most unwanted pests and diseases that could spell disaster for trees and forests if they spread across the UK, such as Chalara dieback of ash (Chalara fraxinea) and pests like the oak processionary moth (Thaumetopoea processionea).

When the deadly chalara dieback disease was confirmed in ash trees growing naturally in the UK for the first time last year, the public stepped up to help scientists, using specially designed apps for spotting, reporting and tracking diseased trees.

There is no reason why this cannot also happen for Chalara fraxinea.

The fungus was first scientifically described in 2006 under the name Chalara fraxinea.

The fungus responsible for the disease was finally identified by scientists in 2006 as the Chalara fraxinea.

Scientists remains unsure exactly how Chalara fraxinea is spread and there is no known cure.

Chlara dieback of ash is caused by the fungus Chalara fraxinea.

Scientists are not sure how the fungus - called Chalara fraxinea - spreads locally but think it might be by rain splash or insects.

At threat from ash dieback (Chalara fraxinea).

Much effort and money is being now put into trying to find out more about ash dieback, which is caused by the fungus Chalara fraxinea.

The Facebook game aims to use the power of social media to find a scientific solution to protecting ash trees from the Chalara fraxinea fungus.

This raised the appalling prospect that Paterson himself might become infected with the lethal Chalara fraxinea fungus.

Ash trees in Denmark showing the characteristic signs of dieback caused by the Chalara fraxinea fungus.

The activities of the ash bud moth Prays fraxinella in spring can also be mistaken for Chalara fraxinea.

He said the best hope was to slow the progression of the disease while searching for ash strains which have natural genetic resistance to the Chalara fraxinea fungus.

There are a lot of different Xylellas out there and this new one would make Chalara fraxinea [ash dieback] look like a walk in the park.

Ash dieback (Chalara fraxinea) has the potential to kill millions of our native ash trees, although the jury is still out on just how devastating this disease will be.

Paterson said: "We know we can't stop Chalara fraxinea infecting our ash trees, so we have to throw our resources into managing it and slowing the spread.

Now conservationists are desperately trying to stop the devastating Chalara fraxinea fungus from spreading throughout Britain's woodlands by calling for a ban on ash being imported into the country.

In 2009, based on morphological and DNA sequence comparisons, Chalara fraxinea was suggested to be the asexual stage (anamorph) of the ascomycete fungus Hymenoscyphus albidus.

That suggests the Chalara fraxinea fungus that causes the dieback could have been present for some years and may have been spread by winds blowing across from continental Europe.

The environment secretary, Owen Paterson, set out plans on Thursday aimed at controlling Chalara fraxinea, including keeping the ban on the import or movement of ash trees in place.

Ash dieback started killing trees in Poland as long ago as 1992, but Chalara fraxinea was not identified as the culprit until 2006 and its exact nature is still being studied.

While filming with Countryfile in Suffolk, Paul Beales from Fera, the government's Food and Environment Research Agency, set up a search for the Chalara fraxinea fungus itself.

The Chalara fraxinea fungus, which causes a disease called Chalara dieback, was first found in ash trees in a nursery in Buckinghamshire in February, The Daily Telegraph reported.

The new centre will also examine how trees can be protected from the threat of invasive pests and diseases, such as the Chalara fraxinea virus which has caused the spread of Ash dieback across the country.

The ash saplings, planted along with other varieties - including oak, birch, alder and wild cherry, have yet to be tested for the Chalara fraxinea fungus but Ms Scott, 60, said the “picture looked grim”.