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identifying the symptoms of Chalara fraxinea, or ash dieback, in the spring
can be tricky. Ash is invariably one of the last trees to come into leaf.
Here we are surrounded by a number of trees in full leaf
we've got hornbeam
cherry and field maple
and yet the ash
has barely flushed.
Depending where you are in the country ash may not come out into full leaf
until late may or even early June.
Generally, the more exposed or further north you are the later it will come into
leaf.
But just because it hasn't flushed doesn't mean it's affected by ash dieback
Remember that not all ash come out into leaf at the same time.
This one hasn't even burst its buds yet.
Compared to this one over here
which is fully in leaf.
Here's an easy way to see whether an ash is healthy or not.
Take a young branch,
scratch the bark,
if it's green it's healthy.
Whereas if you scratch the bark
and its brown underneath
then that's dead.
And if you've got a lot of that material
then clearly that tree is in trouble.
It looks like it's going to take some time
for Chalara symptoms to show on the leaves of the ash.
This tree is really badly affected by Chalara. You can see the distinctive
lesions,
lots of died back,
and yet the leaves still not showing any symptoms.
It may be some weeks or months before the actually started showing the typical
symptoms of ash dieback.
What we would expect to see to begin with are the leaves start to wilt
with black or brown staining on the leaflets and the leaf stalk.
Those leaves will continue to wilt and then die, going dark brown or black but
retained, hanging on the branches.
Later we will expect to see the typical diamond shaped lesions forming on the stems
which are caused by the fungus penetrating into the wood.
So, keep an eye out for ash dieback symptoms in the spring
but don't be surprised if the leaves are late coming out into flush
and don't necessarily expect to see symptoms until late in the summer.
If you want more information on Chalara dieback and its symptoms
please visit the Forestry Commission website.