Natural regeneration: Nature’s grassroots rebellion

There’s a rebellion going on in Britain. All around us. The resistance wins some battles and loses others. It has fought us since we first began to clear woodlands and create fields thousands of years ago. Its aim is reforestation with native trees, its method is natural regeneration, and in more and more places it is winning – increasingly with our help.

Often when trees are felled, worried people want to be reassured that the land will be replanted. People talk as if trees are like a field crop that has to be replanted after harvesting, to avoid leaving the treeless earth bare. Tree planting has an important place, but it must remembered that in most places it accelerates the reestablishment of native woodland, or guides what species will be present. It is not the fundamental and necessary way in which we find ourselves with a woodland. Ask yourself: why would native trees have to rely on human planting?

The fundamental way woodland reestablishes itself is natural regeneration. Trees grow from seeds already waiting in the ground; or brought there by birds and animals; or by undead, overlooked stumps and hedge trees reasserting themselves and breeding a new generation of rebels to lead a local revolution. We can interfere with this process with scythe, brush cutter, and mower. We can delegate the job to flocks of sheep. We can let unchecked populations of deer, rabbits, and grey squirrels put down the insurrection. But the trees keep trying and more and more of us are finding ways to help them.

One of the pioneers of rewilding and reforestation is Alan Watson Featherstone, founder of “Trees for Life” in the Highlands of Scotland. In George Monbiot’s “Feral”, he meets Alan and sees the now inspirational landscape in Glen Affric:

Glen Affric is one of the few parts of Britain in which the work of the Forestry Commission has, from the beginning, been largely benign. Since a sawmill was built in the valley in 1750, the old trees had been under siege, while the sheep grazing beneath them prevented almost all recruitment. The commission bought most of the glen in 1951, and, neglecting its customary duties, decided to preserve it rather than to wreck it. In the 1960s a young forester persuaded his bosses to let him fence 800 hectares of the glen, arguing, against the received wisdom of the time, that the trees could regenerate without being planted. The results were spectacular, an unequivocal rejoinder to those who said it was impossible. We could see them on the brae on the far side of the loch: stockades of pines a few decades old, their spiky profile broken in some places by the great humps of older trees. This experiment was one of the factors that had inspired Alan to found Trees for Life.

An hour’s drive north of Glen Affric is Glen Strathfarrar, and Alan took this striking photo there of forest regenerating naturally, which he has kindly allowed me to reproduce from his blog post. There’s a deer fence in the middle. To the left, trees are coming back naturally with deer excluded. To the right, the trees are scarce and the deer are free to browse any saplings that emerge.

You can’t see the deer in a photo like this, but without their natural predators like lynx and wolves their effect on the landscape is huge. It would be easy to look at a hillside like the one on the right and assume trees can’t grow, if you hadn’t seen what’s flourishing on the left. This emerging wood in Glen Strathfarrar is between about 150m and 250m above sea level, and as we can see this isn’t too high for natural regeneration. (For reference, there are birch woods in Norway at altitudes higher than the summit of Ben Nevis.)

Nature’s rebellion benefits the reestablishment of the forest cover we once had, but it’s increasingly being recognised that increased tree cover could benefit us too. Not just visually and emotionally. Perhaps even financially, and not just with things like tourism. Further south again is Loch Eilt, with this barren hillside at about 50m to 100m that’s been in the news this week. This landslide poured mud and rocks onto the West Highland Line and derailed the first train to come along, blocking the line for days and costing money for Network Rail and the people who finance it (principally taxpayers.)

There are trees in the landscape, including that small wood just to the right of the train. But there could be a lot more, and one of their benefits is to stabilise hillsides and protect against erosion, both the gradual carriage of soil down to rivers and off towards the sea and more dramatic erosion events like this.

With Brexit coming and our eventual withdrawal from the EU Common Agricultural Policy, there’s a debate about how these benefits can be recognised, with concepts like “natural capital” and “environmental services”, and proposals to dramatically increase tree planting. But for now the CAP payments still provide incentives to land owners to keep these barren treeless landscapes. Various euphemisms are used to refer to the natural progression from grassland up to woodland via scrub and pioneer tree species, but they implicitly and unintentionally recognise that the trees’ insurgency will succeed unless checked. As we reconfigure rural policy and support, it mustn’t be assumed that all trees have to be planted. If deer numbers were controlled and sheep removed, woodland could regenerate itself over huge areas without having to wait its turn to be planted.

Nature’s rebellion isn’t just against the moorland landscapes maintained by sheep and deer. Oliver Rackham’s magisterial “Woodlands” describes Shrawley Wood in chapter 19, where the Forestry Commission attempted to replace native lime trees with a conifer plantation:

Shrawley Wood, Worcestershire, is probably the biggest limewood in England. Most of it is nearly solid lime (including one of the tallest native trees in the kingdom). … In the 1530s it had been a wood with common-rights of woodcutting, divided into ten named coppices. …  Shrawley Wood fell into the hands of the Forestry Commission and was given the usual treatment. But Agent Orange here met its match. By 1985 Shrawley was back to being a magnificent limewood, and one had to look carefully for miserable remains of conifers.

I’m seeing the start of something similar at Century Wood, which is a 1980s hybrid poplar plantation, with natural regeneration of hazel plus some ash and oak, and then a few naturalised species like sycamore and horse chestnut. These non-native poplars are susceptible to cankers, and shed their upper branches. Some of the resulting stags are dying, leaving standing deadwood trunks a few metres high. Some of the still living stags are even overstood by the highest branches of the hazel. Even if I wasn’t gradually removing the poplars, they will be gone within a few decades, and the native (and naturalised) species will have won their rebellion.

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