I was up in Scotland at the Royal Botanic Gardens Edinburgh last week and while I was there, I had a good look out for the horse-chestnut leaf miner. There was no sign of it anywhere! Indeed, it was strange to see the horse-chestnuts looking green, unlike in the south of England where they are very definitely browner than all the other trees.
We got a mention of the project in a really nice article in Science Omega on 17th September.
Monday, 24 September 2012
Monday, 17 September 2012
Smaller conkers, says the Sunday Telegraph
Our conkers are getting smaller according to the Sunday Telegraph (16th September 2012). They feature the Conker Tree Science project, and report on an in-depth study (available here) looking at the diminishing size of conkers due to the horse-chestnut leaf miner.
The reports says that "last week, The Sunday Telegraph conducted its own survey of dozens of conkers, found in Green Park and Hyde Park, in central London. Those which had fallen from heavily infested trees were, on average, 15 per cent smaller than those from less affected trees – with an average diameter of around 1 inch in diameter, while those from less effected trees were around 1 1/4 inches."
Just like on the straw polls run during BBC Radio 4's Any Questions, it probably ought to be stated that their survey was not 'scientific' (for instance, they don't assess whether the trees not affected by the leaf miner also started off in better health?), but it's an interesting finding. I'm quite surprised, though, that they managed to find any trees in those areas which were not very heavily infested with the leaf miner!
The reports says that "last week, The Sunday Telegraph conducted its own survey of dozens of conkers, found in Green Park and Hyde Park, in central London. Those which had fallen from heavily infested trees were, on average, 15 per cent smaller than those from less affected trees – with an average diameter of around 1 inch in diameter, while those from less effected trees were around 1 1/4 inches."
Just like on the straw polls run during BBC Radio 4's Any Questions, it probably ought to be stated that their survey was not 'scientific' (for instance, they don't assess whether the trees not affected by the leaf miner also started off in better health?), but it's an interesting finding. I'm quite surprised, though, that they managed to find any trees in those areas which were not very heavily infested with the leaf miner!
Wednesday, 12 September 2012
Making the news
You can see the ITV Meridian news report on the latest Conker Tree Science mission: bird attacks.
We were also featured on BBC Oxford television news, beamed across the whole of the south region, and on BBC Radios Oxfordshire, Berkshire and Humberside.
Derwent May wrote about the project in The Times (30th August) .
We were also featured on BBC Oxford television news, beamed across the whole of the south region, and on BBC Radios Oxfordshire, Berkshire and Humberside.
Derwent May wrote about the project in The Times (30th August) .
Conker tree declines
I've been asked a couple of times recently about the long term prognosis for horse-chestnut trees. The simple answer is "in the worst case scenario, it's bleak".
Here's the background to why we think that is the case:
The horse-chestnut leaf-miner (the focus of Conker Tree Science) does not kill horse-chestnut trees. It does however affect the 'photosynthetic capacity' of the trees. Over the course of a year the 'net primary productivity' (which basically means the amount of food the tree makes for itself) declines by about one-third. (That is according to two scientific papers published in 2004 and 2011.)
At the the same time that the leaf-miner has spread, another more serious disease, called bleeding canker has also spread in our horse-chestnuts. This can cause the death of the tree, and branches that have been badly affected can be dropped by the tree. Local authorities and tree owners have been carefully checking their horse-chestnut trees, and trees have been managed appropriately and in some cases they have been felled.
It is possible that the spread of the leaf miner and the effect it has on the tree's photosynthetic capacity is weakening trees, so making them more susceptible to bleeding canker, though this requires further research.
So, the bleeding canker, may ultimately lead to many horse-chestnut trees being felled. That wouldn't be so bad if trees were being re-planted. However, sales of horse-chestnut trees have declined by 98% over the past 5 years.This is presumably because few people want to replant horse-chestnut trees that look so moth-eaten (quite literally!) by mid-summer.
So, even though the leaf-mining moth doesn't kill our trees, it is intrinsically linked to the possible demise of our conker trees.
Here's the background to why we think that is the case:
The horse-chestnut leaf-miner (the focus of Conker Tree Science) does not kill horse-chestnut trees. It does however affect the 'photosynthetic capacity' of the trees. Over the course of a year the 'net primary productivity' (which basically means the amount of food the tree makes for itself) declines by about one-third. (That is according to two scientific papers published in 2004 and 2011.)
At the the same time that the leaf-miner has spread, another more serious disease, called bleeding canker has also spread in our horse-chestnuts. This can cause the death of the tree, and branches that have been badly affected can be dropped by the tree. Local authorities and tree owners have been carefully checking their horse-chestnut trees, and trees have been managed appropriately and in some cases they have been felled.
It is possible that the spread of the leaf miner and the effect it has on the tree's photosynthetic capacity is weakening trees, so making them more susceptible to bleeding canker, though this requires further research.
So, the bleeding canker, may ultimately lead to many horse-chestnut trees being felled. That wouldn't be so bad if trees were being re-planted. However, sales of horse-chestnut trees have declined by 98% over the past 5 years.This is presumably because few people want to replant horse-chestnut trees that look so moth-eaten (quite literally!) by mid-summer.
So, even though the leaf-mining moth doesn't kill our trees, it is intrinsically linked to the possible demise of our conker trees.
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