The tale of the collapsed oak

12 August 2020 | Posted in Guest blogger , Woods Mill , Plants
The tale of the collapsed oak
The collapsed oak © Steve Tillman

By Clare Blencowe   

On a stormy night in November 2016, the oak tree in the corner of the Mill Ditch Field at Sussex Wildlife Trust’s Woods Mill reserve collapsed: split clean down the middle.

It had fallen neatly at the edge of the field, somehow even missing the five-bar gate that’s now trapped beneath its boughs. After the necessary safety assessment, it was decided the tree would be left to continue its life in this new prostrate position.

Its upper branches, usually inaccessible, revealed a hidden kingdom – mosses and mushrooms carpeted the thick boughs.

PHOTO 2 Tiny mycenoid mushrooms growing on an oak branch Clare Blencowe[1]

Towards its extremities, thinner branches were festooned with lichens in a fabulous array of forms and muted rustic colours. A splash of day-glo pink hints at the presence of a lichen-loving fungus. I could easily lose myself for an hour in the oak tree’s realm – searching for life within its branches.

PHOTO 3 Various lichens admired on a lunchtime walk Clare Blencowe[1]

My colleagues too felt drawn to explore the tree. One lunchtime, a few days after that fateful stormy night, we headed out to search for eggs of the Purple Hairstreak butterfly. This species over-winters in its egg stage, near the growing-tips of an oak twig, waiting for the buds to burst.

Acorn by

Success! Conservation Officer, Jess Price, snapped this photo with her phone of a tiny egg which has been carefully laid in the ‘v’ where the bud joins the main twig.

PHOTO 5 A Purple Hairstreak egg on the collapsed oak Jess price

It didn’t take long for new life to take hold on the virgin surface of the split trunk. In January I came across swathes of Hairy Curtain Crust (Stereum hirsutum) – their rich orange fruit bodies almost glowing in the low winter light.

PHOTO 6 Hairy Curtain Crust (Stereum hirsutum) on the split surface Clare Blencowe

In spring, we headed out to the oak tree again with a beating tray, to see what insect life was chomping on its leaves, or browsing amongst the mosses and lichens. We found its branches teeming with life. A Purple Hairstreak caterpillar was the star of the show for me. This photo shows off its stunning camouflage, so like an oak bud.

PHOTO 7 Purple Hairstreak caterpillar Graeme Lyons

© Graeme Lyons

I was walking through the Mill Ditch Field yesterday. The grass has turned the colour of straw in this drought we’re having. But the oak tree is still incredibly verdant – it’s gone into overdrive producing leaves all over its branches. The vivid green leaves are studded with galls: ‘silk buttons’ and ‘spangles’. Yet more indication of the life supported by this old oak tree.

PHOTO 8 Spangle galls adorn the oak leaves Clare Blencowe

Why not take a look and see what you can see, living in an old oak tree? If you’re lucky you might catch a glimpse of a late adult Purple Hairstreak living out its last summer days.

PHOTO 9 A Purple Hairstreak butterfly Roger Wilmshurst

© Roger Wilmshurst 

Clare Blencowe is Manager of the Sussex Biodiversity Record Centre


  • Louise:

    12 Aug 2020 13:48:00

    Thanks for sharing this story and for the amazing photos Love the lichens.

  • Ginny-Vic:

    13 Aug 2020 10:01:00

    I love how you describe all the moss and fungus – it’s like a poem. Especially “festooned!” I didn’t realise so many things live on trees. There is a tree opposite my house that looks a bit dead and I think they’re going to chop it down. But what if there are things living on it and where will the birds sit? I can definitely see some moss.

  • gailwilson:

    04 Nov 2020 17:45:00

    Of all the times Ive visited Woodsmills, I never actually went over to look at this oak, till today…Close up to it I just went, wow…

    The thought of this huge tree splitting entirely in two, was mind boggling with the thoughtof how terrifying an event for any creature who witnessed it… no humans witnessed it Im guessing?
    Very pleasing to come home & see this very timely report
    Thankyou & thanks tree[s]

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