A day in Inchvuilt Wood

On the second day of my Treelay leg in May, I descended into Glen Strathfarrar down the Allt Innis na Larach Burn. On the lower reaches of the burn I passed by the eastern end of Inchvuilt Wood, a large area of native pinewood on the north-facing slopes of Strathfarrar that I had never visited before. I didn’t have time during the Treelay to wander around in the wood, but I was keen to explore what looked like a beautiful and interesting remnant of the Caledonian Forest, so on a sunny Saturday in early June I headed out there for the day.

Driving along the road in the glen, I stopped near the eastern end, where I saw a large swathe of bluebells (Hyacinthoides non-scripta) growing beside the river, amongst a stand of alder trees (Alnus glutinosa). My impression is that bluebells have been increasing in range and becoming more abundant in the Highlands in the last 10 years or so, but that is just anecdotal, based on my own casual observations – they certainly seem more profuse than I remember from the past.

A little further along in the glen, I stopped beside a good stand of aspen trees, growing in between the road and the river. These all had their new leaves just opened out, so they were copper-coloured and very fresh. They maintain this colour for the first week or two after they unfurl, before changing to their mature green colour. On one of the leaves I saw a bronze beetle – this is a species (Phratora vitellinae) that is common on aspens in our Project Area.

On another leaf of the same tree I saw an aphid, but when I looked closely at it I realised it was actually a species (Euceraphis punctipennis) that feeds on birch, and that is very abundant this year. It must have fallen off, or been blown off, an adjacent birch tree and landed on this aspen. In fact, whenever I’ve been out in the Caledonian Forest in the past month I’ve invariably found aphids of this species crawling on my camera bag or my sleeves – they seem to be everywhere at the moment!

Further along the glen, I stopped again when I saw a group of red deer (Cervus elaphus) feeding near the road. Because the landowner in that part of the glen feeds the deer, they are relatively tame and approachable, and I was able to take some good photographs out of the car window – I knew that if I opened the door, the deer would run away up the hill.

The stags had their new antlers growing, after having shed the old ones some weeks previously. As they grow, the new ones are covered in a thin layer of skin called velvet, and this was clearly visible on them. Some of the deer were just outside a fenced area, where young birches were growing well, safe from browsing. This was a clear contrast to the area outside the fence, where there was no evidence of young trees at all – browsing by the deer will be preventing any from getting established.

My next stop was near a footbridge that provides access to the south side of the glen, just at the eastern end of Inchvuilt Wood, so I left the car there and set out on foot. Once across the Farrar River, I crossed the Allt Innis na Larach Burn (which I had walked down beside during the Treelay event in May), and almost immediately disturbed a bird that was on the ground directly in front of where I was walking. I didn’t get a clear enough view of it as it flew away to identify it, but looking where it had taken off from I discovered a large nest on the ground, directly beneath a clump of heather, with 9 eggs in it. I quickly took a couple of photos, without disturbing the nest at all, so that the bird would return to it once I moved on. I’ve yet to get this bird positively identified, as I didn’t recognise what species it was.

Heading up the hill, I approached the edge of the woodland, where the birches stood out clearly from the darker Scots pines. The birch leaves are a bright green for the first couple of weeks after they open, before turning a deeper shade of green for the duration of the summer. At that stage they’re much harder to distinguish from the pines, but at this time of year, it’s almost as dramatic as autumn in terms of the colour difference between the species.

By this stage it was time for lunch, so I stopped on a rocky knoll, where there was a good view west along the glen. The exposed bedrock clearly showed the sedimentary nature of the geology in this area, with a pattern of layers in the rock.

 

 

 

 

 

 

 

It was a beautiful sunny day, with only a few tiny clouds in the otherwise totally blue sky, and this was one of the most beautiful places I’ve had lunch at for quite a while. Continuing upwards, I entered the woodland itself, which consisted of a mixture of old Scots pines and birches in this section. A few clearings amongst the trees provided some good views back eastwards in the glen.

As I wandered around amongst the trees, I was drawn to an area where some old birches had died, and there were bracket fungi growing out of the trunks and fallen branches. With May and June usually being the driest months in the Caledonian Forest, the tough, persistent bracket fungi that grow out of dead wood are the only fungal fruiting bodies likely to be seen then. Most fungi fruit in September, which is normally one of the wettest months of the year, and they rely on the moisture to be able to produce their fruiting bodies quickly.

There were several different species growing out of some dead birches, and one growing from the trunk of a living birch, although the fruiting bodies of that one were old and blackened.

 

 

 

 

 

 

 

Nearby, on the underside of a large fallen branch of a Scots pine, there was another fungus which I didn’t recognise. I had to send samples of all of these off to Liz Holden, the mycologist who helps me with fungal identifications, and I was delighted when she replied to say that this one on the pine was a species (Dacryobolus karstenii) for which there are only three previous records in Scotland, and therefore a good find.

Coming to a small clearing in the woodland, I got a good view across the glen to the other side, where the landowner had put up a fence to facilitate regeneration of the forest there. This provided one of the most spectacular contrasts between overgrazed land and an adjacent area where deer were excluded. The removal of grazing pressure allows the process of ecological succession to occur again, whereby heather (Calluna vulgaris) replaces the grass-dominated commnity, and then young pioneer trees, especially birch and rowan, become established. Outside the fence, the landscape has become a sad ‘museum piece’, with the vegetation community static and held in a minimal condition – the old trees are dying and not being replaced, and the natural succession of grassland to heathland is unable to occur.

In amongst the pines, where I was, heather was flourishing, and as I walked through a patch of it, my eye was caught by a bright rust-coloured shape in amongst the green sprigs. Looking closely, I recognised it immediately as a cocoon from a moth, which I had subsequently confirmed as the emperor moth (Saturnia pavonia). This is spun out of silk by the moth’s caterpillar in the autumn, and it overwinters in it as a pupa, before emerging as an adult moth the following spring.

Continuing upwards, I came to the top edge of the forest, where it was a similar scene to that I’d seen in Liatrie Wood in Glen Cannich a couple of weeks previously. There were lots of standing dead pines, clearly illustrating that this patch of the wood was dwindling, as there were no young trees growing on to replace the ones being lost, because of overgrazing pressure from the deer.

It was not just the pines that were dying off, as I saw a lone dead birch skeleton, standing stark in a small gully on the hillside.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Just before I turned around and headed for home, I reached a point in Inchvuilt Wood where I could see that the landowner had fenced off a section of it, stretching west from where I was, for natural regeneration. I didn’t have time to walk around inside the exclosure (that will have to wait for another visit to the area), but there were plenty of young trees growing there, so this provided a positive and hopeful note to end the day on.