A problem that takes up a good deal of our time in the summer at Bwlch Corog is Bracken (Pteridium aquilinum). This fern is supremely well-adapted to make the most of the conditions present in large tracts of upland Wales, and is an increasing problem for landowners.
Historically, Bracken was used for many purposes. Before grains were produced in such volume, and their by-product straw so abundant, it was valuable as an easily available winter bedding for livestock. Before synthetic potassium was developed, it was burned to obtain potash – important as a fertilising nutrient and used in the processes of making glass, soap and bleach. The rhizomes were used for tanning leather and dyeing wool. The fronds were also sometimes used as thatching, as a fuel for fires and ovens, and as packing material for transporting fragile goods. These uses meant that large amounts of the fern were cleared each year – but it’s now very rarely harvested. This, along with changing farming practices and the banning of the herbicide asulam, considered the most effective method of control, has meant that Bracken has become a big issue for many land managers. Able to spread quickly and stifle competing species, its uncontrolled spread brings many problems. These include reduction in suitable forage for livestock, reduction in biodiversity as other plants are outcompeted, and increased incidence of Lyme disease – caused by ticks found in high densities in areas of thick Bracken. Most immediately relevant to us at Coetir Anian is the poor survival rate of young trees in areas where it grows thickly.
This impressively resilient fern isn’t able to grow on the very wet, exposed high ground at Bwlch Corog, or to dominate down in the shady Celtic rainforest. But on the ffridd in between, it grows in big, thick patches, and spreads readily – overwhelming saplings by shading them out during the growing season, and by collapsing in the autumn, taking the fragile young trees down with it. Over time, trees that survive long enough to get away above the height of the Bracken will begin to shade it out, reducing its dominance and allowing other flora to find space. Bracken will still grow, but at far lower densities, and in a better equilibrium with other plant life. Indeed, it is a native plant and is important to some animal species such as many of the fritillary group of butterflies, and provides vital cover for some mammals and nesting birds. But without help, few saplings survive long enough to reach above the thick tangle of fronds and provide natural control – so we must manage the Bracken in the meantime.
The banning of asulam has meant that many land managers have had to find new ways to manage Bracken on their land, but as we’ve never used pesticides at Bwlch Corog in any case, we were already using a variety of methods. The quickest of these is with a Bracken bruiser / roller. This is a rolling cylinder drawn behind a quad, a tractor, or horses. We use the latter – Carnog Working Horses, who extract much of the timber felled in our larch plantation, also specialise in Bracken rolling. Barbara and her horses can cover a lot of ground in a day, and rolling an area for three or more years in a row can significantly weaken Bracken growth and slow or prevent further spread.
Given the nature of the areas where thick Bracken is a problem at Bwlch Corog, rolling is not possible everywhere – for instance on steep ground or in areas with high densities of saplings that we want to preserve. Methods that are slower but that can be used in these areas include scything, using slashers or sickles, and strimming. Each of these has its place, but we’ve found that groups working together using manual methods are more efficient than one person with a strimmer / brush cutter. That’s why most of our volunteer days during the summer months, when the Bracken is growing, involve Bracken control. While slashing or scything thick Bracken for hours on end may seem like a thankless task, many of us find the work very satisfying – and looking back at the end of a session to see all the saplings you’ve released from the smothering, impenetrable growth, is particularly gratifying. Having said that, knowing that in two or three years the saplings will be tall enough that we can stop doing it in a given area is even more gratifying.
Bracken in balance
While large amounts of Bracken were historically harvested, by far the biggest controlling factor was the presence of cattle. Cattle were historically farmed far more extensively in upland Britain than today, and their trampling caused a constant weakening effect – breaking and bruising stems and breaking up rhizomes. We try to recreate this at Bwlch Corog, by having the cattle spend time on the ffridd each autumn – between spending the summer on the upland eating the Purple Moor Grass (Molinia caerulea) which dominates there and heading down to lower ground for the winter. This has to be managed carefully, as if the cattle start to run out of suitable forage, they may begin to eat the Bracken itself – which is toxic in large amounts. If the ground is very wet, the cows heavy movements can ‘poach’ the ground – breaking through the surface and exposing the soil, causing soil erosion. And, as was the case this year, during a mast year when unusually large numbers of acorns are on the ground, combined with a very dry summer resulting in poor grass growth, cattle may be tempted to eat the toxic acorns, causing them to become unwell – or worse. So while cattle are a useful tool to combat the spread, they are a tool we must use sparingly.
The battle with Bracken is not one that will be ended quickly for us. As more trees grow tall enough to cast shade, we will be able to step back from those areas and allow nature to take its course. There is suggestion that the effects of climate change – particularly warmer winters – will make it possible for Bracken to spread to areas that weren’t previously suitable, and we may have to expand the battlefield accordingly. But for now, we’re confident that by continuing to employ a mix of methods and help our saplings to reach maturity, we’ll see success in the long term. In the meantime, we’ll be keeping an eye on other methods that are being employed elsewhere, such as using pigs, remote-controlled self-propelled rollers, and protective tripods placed over saplings, with an open mind about their possible utility at Bwlch Corog.