Bannau to Bog – August 2025

In August I dropped the daughter off at Bannau Brycheiniog for her assessed DofE Gold expedition and then travelled north towards Tregaron to visit Roger.

Along the way I stopped off at Cwm Rhaeadr Forest hoping to chance upon some interesting slime moulds or fungi. I wandered through the woodland ending up at the waterfall.

From the waterfall, I decided to scramble north up the steep flanking hillside and onto the upland plateau east of Mynydd Mallaen, overlooking the Cwm Rhaeadr woodland.

Above Cwm Rhaeadr looking south east, left to right – Pen y Fan, Fan Brycheiniog.

My daughter and her team would be on their final ascent to Pen y Fan and it would be heaving – on this upland plateau of Mynydd Mallaen I was likely the only person.

I wasn’t really trying but I was disappointed that I hadn’t noticed any slime moulds or fungi, that is until returning to the car park I spotted a dense cluster of fruiting bodies on a pile of wood chippings

I think these could be Gymnopilus dilepis – the magenta rustgill. Various online resources state that this fungus can occur on woodchip and although its previously been considered a rare find, it’s likely to be increasing in the UK.

At Tregaron, Roger & I visited Cors Caron nature reserve. Near the entrance I spotted something that wasn’t what it seemed at first! A fungus in an advanced state of mouldiness.

The bird hide at Cors Caron is a timber-framed, timber-clad building designed by architect Arwyn George. Having worked with timber frame construction myself, it’s always interesting to see this form of architecture – I’m particularly drawn to how these structures are put together.

But perhaps it’s not such a great idea to have timber shingles as a roof covering for a building on the western edge of the Cambrian mountains! The shingles were heavily populated with dry lichen, and hidden fungal life would be waiting for the right damp moment to stir into life. In this orographically-drenched landscape, the timber isn’t just a roof – it’s a fungal substrate, a biological sponge!

Some of the shingles were missing, and there didn’t appear to be any counter battens. This limits airflow beneath the shingles and reduces the roof’s ability to dry effectively.

Likely though, the use of timber shingles was a deliberate choice chosen for the way they would blend in better with the landscape, weather naturally over time, and soften the sound of the rain.

There’s been growing use of recycled plastic in conservation work, and I find myself conflicted about it. Timber needs to be treated, but eventually it does rot – and, like the timber shingles, it becomes a substrate for biological growth.

I was bemoaning that this doesn’t happen with plastic, when I spotted some lichen thriving at the edge of the boardwalk!

A lizard basking on the boardwalk post.

Returning to the Bannau Brycheiniog DofE base, despite the poor forecast, I decided to squeeze in a hike up to Pen y Fan. I prefer not to set out too late – it was 11am – the conditions from Coedwig Taf Fechan car park were already utterly wet. At Filter House I had meant to walk toward Bwlch ar y Fan, but found myself heading west up the steeper slope to Graig Fan Ddu instead.

On reaching the ridge, the rain abated, but visibility was low. As I approached Corn Du the rain intensified and the wind picked up sharply all the way to Pen y Fan.

I descended down along Craig Cwm Sere and veered off onto the Beacons Way, bypassing Cribyn, to Bwlch ar y Fan. I was out of the cloud but not the rain, and there, in the upper Blaen Taf Fechan valley were shepherds herding their sheep!

As a family we had been on Pen y Fan before but the last time I was here by myself was in 1990.

Mynydd Mallaen at Wikipedia
https://en.wikipedia.org/wiki/Mynydd_Mallaen

Cwm Rhaeadr information
https://naturalresources.wales/days-out/places-to-visit/south-west-wales/cwm-rhaeadr

Cors Caron at Wikipedia
https://en.wikipedia.org/wiki/Cors_Caron

Cors Caron information
https://naturalresources.wales/days-out/places-to-visit/mid-wales/cors-caron-national-nature-reserve