Dead wood fungi in Glen Affric

In the middle of February, after I’d returned from a 3 week trip abroad, I made my first photographic trip to Glen Affric of 2015, together with my partner. It was an opportunity for us to spend a day out in the Caledonian Forest together, and although there had been quite a lot of snow when I was abroad, it had melted during a recent thaw, and there were only small scattered patches left, at least at low elevations in the glen.

When we arrived in Affric, I didn’t have a specific destination in mind, but, as is often the case, was trusting my intuition to lead me somewhere of interest. So it was that we’d just passed Dog Falls, and were driving further west, when I spotted a cluster of birch polypore fungi (Piptoporus betulinus) on a standing dead birch tree beside the road. I suggested stopping there, so that I could take some photographs, and as it turned out, we spent at the rest of the day there.

The attraction of the fungi proved significant too, because there were a lot of dead birch trees (Betula pubescens) in the area, and although I didn’t plan it, the fungi fruiting on them became my main subject for the day.

 

 

 

 

 

 

 

In addition to those on the dead birch trunk, or snag, as such standing dead trees are called, I spotted a number of other birch polypore brackets on fallen birch trunks and branches. It soon became apparent that there were quite a number of old birch trees in the area, which had either fallen over of their own accord, or had been blown down in the storms that seem to be becoming more frequent in the Highlands. For example, I wrote a blog about the trees that were blown down at Dundreggan by the powerful storm of 5th December 2013, while another one on 8th January 2015 felled a lot of trees in Inverness-shire, including some in Glen Affric, but, fortunately, very few at Dundreggan.

It looked like one or two of the birches in this area had come down recently, and although they didn’t appear to have any fungal fruiting bodies on them yet, there were plenty of other fallen birches that did. On some, the birch polypore fungi were fruiting amongst clumps of lichens, such as beard lichens (Usnea spp.) and frilly lettuce lichen (Platismatia glauca), which would have been growing on the trees while they were still standing.

I’m not skilled enough to tell the various Usnea lichens apart, and when I emailed the photos to John Douglass, who helps me with identifications, he said he was unable to determine the correct species, as he would need specimens for that.

 

 

 

 

 

 

There were other lichens on the fallen birches as well, and one trunk had a good colony of one of the dog lichens (Peltigera membranacea) on it. Another one had a couple of patches of cudbear lichen (Ochrolechia tartarea) on it. Both of those had lots of apothecia on them – the disc-like structures that release the spores of the fungal partner in the lichen symbiosis – but the patches were quite different to each other, not only in coloration, but also in the distribution of the apothecia.

Cudbear lichen is quite common on old birch trees, and is distinguished by its apothecia, which are sometimes referred to as ‘jam tarts’, because of their mainly circular shapes and white rims. In looking at these two patches it would be easy to assume they were different species, but in fact there is quite a lot of variation within the species, particularly in terms of the colour of the thallus, as the main body or structure of the lichen is called.

 

 

 

 

 

 

 

After a brief diversion with the lichens, it was the fungi on the dead birches that drew my attention again, with one birch log in particular having an abundance of fruiting bodies on it.

 

 

 

 

 

 

 

There was a cluster of the fungal brackets on one section of the trunk, with some of them looking almost like they had flowed across, or been poured over, the log. The partially-peeled off brown skin of the fungi gave them quite an artistic appearance, and a dead birch leaf looked like it had been artfully placed in the perfect position by the wind.

Near the base of the fallen trunk there was an old specimen of a birch polypore fungus, which had obviously fruited before the others. Its surface layer was peeling off, and the decomposition process had already begun to take place on the inner structure.

 

 

 

 

 

 

 

Unlike the tinder fungus (Fomes fomentarius), which was also fruiting on this fallen birch trunk, the birch polypore is relatively soft-bodied, and its individual brackets do not survive for such a long period of time. However, they can still persist for up to a year, although this pales in comparison with the tinder fungus, whose tough woody brackets have been recorded as surviving for up to 22 years. With my love for detail in Nature, I found the patterns of the peeling surface to be aesthetic and artistic in their own way.

 

 

 

 

 

 

 

 

 

Further up on the same fallen birch trunk there were a number of tinder fungi, and these were displaying a range of colours, with some younger ones being brown while the older brackets were more grey in colour.

 

 

 

 

 

 

 

There were a number of standing dead birch trees in the vicinity, which also had tinder fungi fruiting on them, including a real ‘veteran’ tree – a very old birch with a substantial, gnarled trunk that was covered in mosses.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In addition to those on the birch snags, I found some tinder fungi on a fallen birch, and one bracket was covered in cypress-leaved plait-moss (Hypnum cupressiforme).

 

 

 

 

 

 

 

 

 

I’ve photographed moss like this growing over tinder fungi before, and I often think that the combination of bryophyte and fungus makes for some aesthetically-pleasing images.

 

The tinder fungus can be quite varied in both colour and form, and as I continued to look around, I found some good examples of this. On one birch log, for example, a group of brackets that were fruiting together had been bleached by the sun, wind and rain to a very pale grey, almost white colour. The colour is dependent to some extent on the daily conditions, for the darker grey brackets turn almost black, with a shiny appearance, when they are wet from rain.

On one of the fallen birch trunks I found a good colony of one of the dog lichens. This was a different species (Peltigera hymenina) to the one I’d seen earlier, and was covered in an abundance of brown apothecia. As with the other dog lichen (Peltigera membranacea) that’s in the photograph further up in this blog, this one had rhizines – white downward-pointing spines – visible on the underside of its thallus.

 

Rhizines like this are a distinctive feature of many of the dog lichens (Peltigera spp.), and are root-like in their function, as they are the means by which the lichen attaches itself to the substrate it grows on.

 

 

 

 

 

 

 

On a different fallen birch trunk nearby I spotted another fungus, and this was one that I didn’t recognise. After photographing it I collected a specimen (there were several there altogether), which I sent to Liz Holden, the mycologist who helps me with the identification of fungi. She replied that it is a species called the bay polypore (Polyporus durus), which is common throughout much of Britain and has a tough brown cap with dense white pores on the underside.

There were a number of small patches of snow still remaining on the ground in this area, most likely where the wind had blown it into deeper drifts that hadn’t quite melted yet, because of the greater (cold) thermal mass these patches contained. On one of these, a small section of a frond of bracken (Pteridium aquilinum) had fallen, and the snow provided an ideal background that allowed the structure of the frond, and the pattern of the leaflets on the frond, to be clearly visible.

As I walked around, looking for more fungi on the fallen birches, I spotted one birch trunk with a lot of tree lungwort (Lobaria pulmonaria) on it.

 

 

 

 

 

 

 

This immediately struck me as being quite unusual, and, in fact, I don’t recall ever seeing tree lungwort on a birch before. It is common on other tree species in wet parts of Glen Affric, such as rowan (Sorbus aucuparia), aspen (Populus tremula), goat willow (Salix caprea) and oak (Quercus petraea). Birch is generally considered to be a relatively poor host for lichens, perhaps because of the low ph of its bark, so that may account for the relative rarity of tree lungwort growing on it.

By this time we were almost ready to head for home, so I returned to the road, and just beside it I discovered another different fungus growing out of dead wood. In this case I thought it was the turkeytail fungus (Trametes versicolor), that was fruiting on the cut stump of a small Scots pine (Pinus sylvestris), but when I sent a sample to Liz Holden,  she told me that it was actually a related species (Trametes ochracea) – one which doesn’t yet have a common name.

The brackets of this species are thin but tough and leathery, and are slow to decay, resulting in them being visible all year round. The concentric pattern of rings provides an indication of how the brackets develop and grow, and make for interesting visual images. They are typically pale brown to cream in colour, and the undersides are covered in pores, instead of the gills found on most mushrooms.

In fact, I only noticed these bracket fungi because I was on my way to see some cascades on a small burn just above the road, and they were a few metres from the watercourse. The burn itself formed a very nice finale to another unexpected day, spent almost entirely in the company of various fungi, all within about 200 metres of where we had parked the car!