Chris Catling, Royal Commission on the Ancient and Historical Monuments of Wales Secretary tells us about his love for maps as part of our #LoveMaps campaign.
OS 6-inch Cards XXI N.W 1st edI have chosen this map because it shows something very rarely seen on any map, a great peat bog, which extends for some 8km (5 miles) north eastwards from Tregaron to Ystradmeurig, in Ceredigion.
Cors Caron in Welsh, and Tregaron Bog in English, has taken 12,000 years to form, beginning at the end of the last ice age, around 10,000 BC. Bogs like this occur in very flat landscapes that are waterlogged for much of the year. Sedge colonises the wet landscape and when these perennial plants die back each year, the debris gradually accumulates at the rate of around 1mm a year. In time the accumulated peat forms a dome rising above the water table, and it is at this point that trees and shrubs can begin to colonise the landscape – water-loving plants such as sallow and alder first, then birch forest, and finally oak and ash.
The reason why this bog –– is still an open flat peatland landscape and not a dense wood, is that the bog has been managed over the centuries. Local farmers once harvested the sedge for thatch, bedding and fodder, and the peat was dug for fuel for generations. The bog once formed a part of the extensive estate of the Cistercian monks of Strata Florida, and they regarded it not as a bleak wasteland, but as a useful source of fish, eels, wildfowl and peat, as well as rough grazing for cattle and horses.
It is said that some of the rectangular pools that you can see if you visit the bog today are the remnants of monastic peat digging, but this Ordnance Survey map – surveyed in 1887 – does not show them. It is probable that any medieval workings long ago reverted to peat and that today’s pools and channels (like the Norfolk Broads in miniature) represent more recent extraction.
The map shows the River Teifi snaking through the middle of the bog, while the former Aberystwyth to Carmarthen railway, which opened in 1866, runs along the bog’s eastern edge. Laying the track through the bog was quite a challenge: it rests on a bed made of sacks of wool instead of the more normal ballast. This unconventional approach seems to have worked as the track does not flood and is now used as a footpath for visitors to the bog.
There is talk of re-opening the line – if so, it will probably have to take a slightly different route because today Cors Caron is an important National Nature Reserve. It is well worth a visit not only for the eerie atmosphere but also for the rare flowers – such as marsh cinquefoil, asphodel and bog bean – the lizards that bask on the sun-warmed wood of the board walks crossing the bog, the moths and butterflies and to enjoy the sights and sounds of the more than 70 species of bird that nest and feed here.
This post is also available in: Welsh