Oak. Every Tree Tells a Story. Part two.

The Many Species of Coed Y Brenin

[continued from the previous piece]

above: dead oak, shaded out by conifers, in this case both an overstory of mature Norway spruce and a rapidly growing understory of western hemlock.

In the mid 1990s the then Comisiwn Coedwigaeth, Cymru (Forestry Commission Wales) formally abandoned any sort of management of the older part of Coed Y Brenin, including the Core Block of Mynydd Penrhos. The only work that was carried out (apart from the new mountain bike trails and footpaths, funded by European Access grants) was the clear-felling of relatively small patches of conifers in order to keep some experience in the workforce.

This meant that some of the almost smothered oaks were suddenly liberated and once more surrounded by light. Unfortunately, this meant that for many, deprived of the shelter they had grown used to and with roots compromised for decades by the growth of the conifers, the first strong gale brought them down.

above: the lower branches of this oak tell us it started as open grown tree. From the fact that they have died back we know that it then experienced dense shade as the conifer plantation grew up around it, forcing it to grow ever taller for the light. Then, the conifers were clear felled, leaving a top heavy tree with roots that had been restricted by the conifers. All too often this is the result.

As a fallen tree they do struggle on as new branches grow upward from the trunk, triggered by the newly available light but It would seem much better to coppice them while the clear-felling was going on and avoid the enormous root damage wind blow causes. No matter, some do survive and their responses are recorded in their changing form and growth patterns; suddenly exposed to light all round, dormant buds on branches and trunk are triggered into growth and the tree takes on a hairy appearance.

above: an oak, again previously open grown, then surrounded by conifers planted in 1967, the lower branches shaded out and dying back, growing tall towards diminishing light. Then the conifers clear felled and dormant buds triggered by the new light, producing twigs and small branches over the entire surface of the trunks, giving a hairy appearance. This one has so far survived the gales.

There’s a hedge remnant quite close to us, reaching up for the light between two stands of conifers, some already dead, some dying. These represented old stock, the oak probably descended from the trees that made up the original forest of Penrhos before it was felled in the late 1500's. It seemed a great shame that these trees were doomed to die out, the seed they produced, if any, simply falling into deep shade. Then, amazingly, both sides were clear felled, the dying trees recovered, putting out more branches and leaves. Then wind blown seed of western hemlock swamped the area and within ten years they were again struggling to reach the light. There is only so much a guerilla forester can do...

above: a hedge remnant of hazel and oak that survived the dense shade cast by the first generation of forestry only to then be threatened now by the even denser shade of self seeded western hemlock.

A fairly unique characteristic of oak is that it has two growth phases, one in the spring, as most other trees but then a second phase in the autumn, coming around the beginning of August, hence the name, Lammas growth. This is very noticeable by a colour change in the stem and leaf, often red but can be yellow or orange before gradually turning green and the hardening to regular looking bark.

above: Lammas growth on oak, coppiced (probably accidentally) during clear felling of diseased larch. The Lammas shoots burst out in August, their colours, ranging from reds through to oranges, as here, making them both striking and obvious.

Lammas growth can be considerable, sometimes much greater than spring growth. An acorn lodged on the edge of my polytunnel, a privileged position, having the benefit of additional water running off the tunnel, its roots penetrating the cover and reaching into the rich beds inside and the outside surface being a mown path. In its third year it grew 45cms in the spring and a whopping 95cms in August. And people say oaks are slow growers!

above: oak growing in a very favourable position on the side of our polytunnel. The green marks drawn on show the spring growth (between the two marks) and the Lammas shoot (beginning above the top mark). Similar, slightly lesser Lammas shoots sprout from the other branches, though I haven’t marked these.

One other characteristic worth mentioning which is very visible on oak here, is the vast numbers of lichens they will support. At certain times of year, like the early spring, before the leaves are out, they can look like they are shrouded in snow or have sprouted some strange, abundant flower.

above: large oak showing a considerable growth of lichens. In the foreground is blackthorn showing similar quantities of a different lichen. Note that the conifers behind generally do not present any surfaces suitable for lichens although occasionally they do.

Last words on oak, literally; the word oak in Cymraeg (Welsh) is derwen which gives rise to names such as the river Derwent in Cumbria and in Cymraeg is very close to derwydd or druid. From various classical accounts (notably Julius Caesar) oak is mentioned as the sacred tree of the druids. Stumbling through the dense, dark thickets here in the 1980's and suddenly coming across these mounds surmounted by clusters (groves?) of oak was a magical experience.

above: every tree tells its own story. A hedge remnant, in this case a single oak, previously laid in a hedge, presumably with other species such as hazel which have now vanished, very heavily shaded on the side the picture is taken from by Norway spruce planted in 1927 and now coming up to 100 feet tall (say 30 metres) with a dense understory of western hemlock at 40 feet tall (about 12 metres).

Looking to the future, some of the small patches of clear felling that were carried out each year were left to regenerate with whatever seed was in the ground. The result was more interesting mixed stands of conifers and native hardwoods, including cherry, no doubt spread by birds; as yet I have been unable to discover the source of the cherry seed.

These mixed stands are moving into the thicket stage and present tremendous opportunities to develop and trial the sort of recombinant ecologies that David Holmgren discusses¹. However, without selective intervention these regenerating stands can all too easily come to be dominated by the more tenacious conifers, in particular western hemlock which seems to be able to outcompete and shade out pretty much anything, including rhododendron in some situations. I've mentioned western hemlock in a number of previous pieces but as it is now apparently the commonest conifer in Britain and is likely to become even more of a challenge to native species than rhododendron, I will be covering it in some detail in a separate Many Species of Coed Y Brenin article.

Finally…a picture that I forgot to insert into the first half (my bad!). I was talking about the tendency of oak branches to split through twisting in high winds.

above: a split on a lower branch of the barn oak, weakened by being shaded by branches above and being remarkably long (over ten metres) and hence very prone to movement in gales. The branch at the split is about 18 inches in diameter (450mm).

Thanks for reading and a warm welcome to you new subscribers. Next up is something about art and in particular fiction; what's all that about then? Is it useful, helpful? Can it influence us? Change our opinions? Plus a chapter list of Konsk the Patafiction, all the episodes so far here on Substack, so new subscribers can catch up easily but only if you should want to; nothing is compulsory! Feel free to bin the stuff that doesn't interest you but I do hope to hook some of you in...And that will be followed by several more episodes of the epic. Take care all. Hwyl! Chris.

1. Briefly, recombinant ecology suggests that the combining of species from different countries and continents can result in ecologies which are more resilient and productive than local, native ecologies. The separation of the supercontinents (Gondwana and later Pangaea, 200,000,000 BCA) led to the isolation of genetic material on separate continents and thus allowed for the evolution of different genetic solutions to a much wider range of environmental challenges.

The process of recombining that diverse genetic material and the many species that embody it has been occurring for many centuries (millennia) and has been doing so with increasing speed due to the increasing ease of human travel and transport. Given also the rapidly changing environmental conditions caused by global warming, recombinant ecology suggests it would seem futile and even absurd to attempt to preserve purely local, native species and instead we should take advantage of the increasing diversity of species we have available to us today to create and trial new ecologies which may be both more resilient in the face of global warming and more productive in ecological and human terms.

David Holmgren’s website can be found here.