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>>CHARLES LANE: So we've come to a pantation today to look for symptoms of ash dieback.
Here you can see a healthy leader of about a three-year-old tree. But what we're looking
at today is this wilting of the leaves and these are the symptoms you're likely to see
in late spring and early summer. When you look at this you can see how the leaves have
wilted, but actually this is because there's been damage lower down here. If you look down
the bottom of the stem you can see how there is discolouration of the wood. This actually
is where the fungus has infected, caused the disease and then it's resulted in the leaves wilting.
I'm standing in a mixed woodland now looking for symptoms of ash dieback on some slightly
more mature trees. These are probably about ten- or fifteen-year-old trees. If we look
up at this tree here, we can see the wilted stem, which is characteristic. That's because
the stem has been killed higher up by the disease. If you go above that stem and then
trace it you can actually see the dead stem there, and that's classic symptoms of
the wilting of ash dieback.
So again here we're looking for symptoms of ash dieback. As you move up the main stem
you can see that the branches either side are all dead giving the tree a very thin
looking appearance.
So here's one of the most diagnostic features of ash dieback. You can see this very characterstic
diamond-shaped legion. This is due to infection coming in through the side stems and then
spreading into the tissue like this causing that dagger-shaped legion.