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.
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.
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.
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.
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.
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.
© 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.
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.
© Roger Wilmshurst
Clare Blencowe is Manager of the Sussex Biodiversity Record Centre