Snowdonia from the Air

Llyn Trawsfynydd

Snowdonia from the Air

Patterns in the Landscape

Snowdonia is renowned for its natural beauty, as recognised in its designation as a National Park, but the extent to which man has contributed to the formation of its landscape is less well appreciated.

Millions of years of uplifting and erosion have modified the solid geology into a series of mountain blocks cut by deep valleys. It is only some 10,000 years ago that the remnants of the last glaciers disappeared, leaving behind characteristic rocky cwms and steep sided U-shaped valleys, some filled by deep lakes. The ice stripped the upland areas to bare rock and left the lower slopes covered in moraines and sheets of boulder clay.

Tomen y Mur and Llyn Trawsfynydd

Tomen y Mur and Llyn Trawsfynydd © RCAHMW 965503-18

After the ice retreated erosion and re-deposition by wind and water gradually created a soil cover, filling the valleys  and the coastal plain with gravels and silts. Plants, shrubs and trees slowly filled the landscape, and fauna of all kinds colonised the area. Even the higher mountain slopes were once covered with trees, the remains of which can sometimes be seen below later peat deposits. These transformations were all the result of climate and natural processes, until about 8,000 years ago when man began to use Snowdonia as a place to hunt and forage.

From about 4000 BC we have evidence of Neolithic people starting to settle and farm, constructing their distinctive burial chambers and ritual centres. From this time onwards man has increasingly modified the landscape. Stones were cleared from the surface to make agriculture possible and to construct field boundaries; mineral resources and stone of special quality were discovered and used to make tools. A major change, clearly seen in studies of pollen preserved in peat bogs, was a gradual decline of the tree cover, due to land clearance, to browsing by animals and to the use of timber both for building construction and for domestic and industrial fuel. Climate still had a significant influence, both on the vegetation cover and on the pattern of settlement. In drier and warmer periods the population would have increased and the upland areas would have been used more intensively. In colder and wetter times the high farms and fields would have been abandoned. Eventually denuded of trees, the upland soils became more acid and peat bogs began to form. From the Roman period onwards we begin to see more clearly the influence of social, political and economic developments, all contributing in recognisable ways to the increasing rate of change in the landscape.

However wild and untamed it may appear, there is little of Snowdonia in which we cannot see the influence of man, either indirectly through changes to the vegetation cover or directly through physical modification of the ground.

Egryn, Dyffryn Ardudwy

Egryn area, Dyffryn Ardudwy © CUCAP RC8-EZ-174, 1983

The western slopes of the Rhinogydd, between Harlech and Barmouth, have perhaps the most intricate of all the landscapes in Snowdonia, as illustrated in this remarkable vertical photograph from the Cambridge University collection. The narrow coastal strip, with the richest land, has been intensively cleared and enclosed into an irregular network of fields, but even here there are still traces of older field boundaries and prehistoric enclosures (bottom centre).

The steep slopes in the top half of the photograph, which have deep and well drained glacial clays, are covered with abundant traces of early agricultural activity and settlement of several periods, forming an intricate and almost continuous ancient landscape. Readily visible are a prehistoric hillfort (top left), several other prehistoric settlements, field boundaries, clearance cairns, cultivation ridges and a variety of Medieval and post-Medieval settlements. Beyond, on a higher plateau, are remains of Neolithic and Bronze Age cairns, stone circles and settlement sites. This upland area was enclosed in the early 19th century by a remarkable series of linear walls running to the summit ridge of the Rhinogydd, shown more clearly on later photographs. The coming of the railway resulted in the development of tourism along the coastal strip and part of one of the extensive caravan parks can just be seen. To the seaward side of the shingle bank are remnants of early forests, covered by deep peat beds, flooded by post-glacial sea level rises and now being rapidly eroded by the sea. Even in this zone traces of early field systems can be seen below high water mark. The centre of this photograph is at about SH 602 206.