a somewhat occasional blog

#Treeyear July – Bit of History and the Leaf Miner Moth

My two #treeyear trees have been a bit overlooked in my blog. Firstly I was away for a lot of may and have since been a slightly preoccupied with blogging about the wildlife and birds I saw in Colorado. However I have not been ignoring them. The Horse chestnut tree’s leaves have been transformed from a brilliant green to pale patchwork of blotches, whilst the Lime is full of seeds that are about to drop.

Horse Chestnut tree with Leaf miner Moth blotches

British conkers under threat from alien moth invasion

My mystery blight on my Horse Chestnut was cleared up today, when I took a look at the Guardian’s Environment Page:

‘Detecting leaf miner activity is child’s play, like conkers. The caterpillars cause large, whitish blotches on leaves which then shrivel and turn brown. Inexhaustibly greedy, the larvae live in colonies as large as 700 on a single leaf and can defoliate a large tree by midsummer, leaving it apparently dead.’

So my blight is actually the work of leaf miner moth – the Horse Chestnut Leaf Miner (Cameraria ohridella), just as my lime was ‘attacked’ earlier in the year by Lime Tree red spider mite. An according to the article this little moth, which has spread across Europe could threaten not only our traditional children’s autumn play but also the tree itself. I read this with a mixture of alarm. Not because of the moth’s antics but because the article claimed that a tiny moth might destroy, not only our traditional game, but by implication a mass slaughter of our trees. A moth against man. Methinks man is more of a threat to trees than a moth!


As I said I was away for a lot of June – in Colorado. Which brings me to history, for when I was high up on Mt. Evans I stood next to in a grove of Rocky Mountain Bristle-cone Pine (Pinus aristata), I was told by my colleague Manfred that he had heard that this were some of the oldest trees in the world –

‘It is a long-lived tree, though not attaining the longevity of Pinus longaeva. The oldest known tree, which grows high on Mount Evans in Colorado, was found to have at 2,435-year tree ring record. However, trees rarely live over 1,500 years.’

But then again the oldest tree in the world is actually a Bristle-cone Pine Pinus longaeva – Methuselah – the has watched the passage of time in the White Mountains of California for 4841 years!!!

So on my return I got thinking about how old my trees were, and in particular the  Horse Chestnut. Of course I knew it’s age would pale into insignificance compared to the Bristle-cone Pine but it would be interesting to know. But how to know? I wouldn’t want to get a  chainsaw and cut the tree down to count it’s rings:

  • I am attached to my tree after 22 years and even more since my #treeyear started
  • There would be a gaping hole  with nothing but a brick wall to look at
  • I would probably get arrested! (Rightly so).

Well a bit of detective work was called for.

The Oldest Horse Chestnut in Europe

Apparently the oldest Horse Chestnut can be found in Sicily and is called the Hundred Horse Chestnut. It is possible that the tree was in existence in around in 1476 as  legend goes the young Queen Joan of Aragon rested under it with a hundred retainers. That would make the tree pretty old – at least 535 years old. And if it could shelter a 100 retainers it must have been pretty big  so perhaps it could be nearing 1000 years old?

Then I hit on the 10 Oldest trees, which says that the Hundred Horse Chestnut is believed to be between 4000 – 2000 years old. Wow! My tree is no pensioner (this is not derogatory) – my tree must be a teenager in comparison.

So when was it likely to have been planted? As I live in the Dartmouth area of Blackheath, which was enclosed by Lord Dartmouth, perhaps it was planted then.

Late in the seventeenth century, when houses began to appear around the north-western corner of Greenwich Park, and Lord Dartmouth enclosed some land on the western edge of the common and built the fine street that he called Dartmouth Row.

So there is a good chance that my rather youthful Horse chestnut is 300 years old.

BiodiversityInternational Year of the Tree

All this talk of history has given me a sense of what my tree might have seen – the discovery of Longitude over the way in Greenwich Park, the arrival of the railways, the bombing of the second world war and the infilling of Blackheath with the bricks and mortar of the war. And now unknowingly it is witnessing  the International Year of Forests (IYF) of which the tre year project is an ‘expression’. And the IYF is part of the International Decade of Biodiversity, which brings me back to the Horse Chestnut leaf miner. Although it’s antics threaten our Horse Chestnuts and have certainly discoloured mine, this moth was only discovered in 1984 in Macedonia, by Lake Ohrid. It has only been known to science for 37 years!!

What more is there to be discovered about the world’s biodiversity, whether it be harmful to a tree, and let’s be celebratory here for the moth itself is an attractive thing. So support the IYF and the Decade of Biodiversity, because trees are rapidly being taken out of action by humans in a more damaging way than by a mere moth.

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