It is hard to picture the former iron industry in today's countryside of small fields, woodlands and steep, narrow, gill valleys. But in this landscape exist all the necessary raw materials that allowed iron to be smelted for over 2,000 years.
The Wealden geology of sands and clays yielded the iron ore, as well as the stone and brick to build the furnaces; the woodland provided the charcoal fuel; and the numerous small streams and valleys ensured water power for the bellows and hammers of the forges and furnaces. For two periods - in the first two centuries of the Roman occupation, and during Tudor and early-Stuart times - the Weald was the main iron-producing region in Britain. Julius Caesar first drew attention to iron being produced in the coastal parts of Britain. Archaeologists have found evidence of iron working from the late Iron Age at sites near Crowhurst and Sedlescombe in the south-eastern High Weald.
Roman iron production
When the Romans invaded in AD 43, they found a well-established local tradition of iron making, using small, clay bloomery furnaces. With growing markets generated by the building of towns, villas and farms, the Romans encouraged this native industry. Sites from the period have been found all over the eastern part of the High Weald.
The 'Classis Britannica', or British Fleet, an imperial supply organisation as well as a navy, took a strategic role in iron production. It managed several large smelting sites in the area around Hastings, such as one at Beauport Park, near Battle. This may have produced as much as 30,000 tonnes of iron over 150 years, and a substantial bathhouse was built there for some of the workforce.
Iron production in the middle ages
We know little about iron making in the Weald in Saxon times, and the industry receives only one mention in the Domesday Book for Sussex, at a location near East Grinstead. However, during the Middle Ages iron production grew steadily, concentrated more in the northern part of the Weald. Accounts have survived from 14th-century works at Tudeley in Kent, and excavations have confirmed medieval references to iron makers in Crawley and near Horsham. Towards the end of the period, waterpower began to be used for forging iron, heralding the introduction, in 1496, of the blast furnace.
Introduced from northern France, and operated by skilled, immigrant workers, the blast furnace was a much larger, and more permanent structure than the bloomery; and instead of a few kilos of iron being made, daily output was nearer a tonne.
More ore and charcoal were required, and the need to operate the bellows by waterpower, instead of by hand, meant that ponds had to be created to store the water. In addition, the higher temperatures in the furnace meant that a different type of iron was being produced. A second process - the forge, with its own pond and supply of charcoal - was needed to refine the iron.
By the mid-16th century there were 50 furnaces and forges, and that number had doubled 25 years later. All over the Weald, the iron industry was having an effect, with large numbers of people employed in digging ore, cutting wood and transporting both raw materials and products.
Most furnaces made 'sows', or lengths, of iron for refining, but from the 1540s a small number began to make cast-iron cannon, a product that grew to be a profitable, and sometimes illegal, export.
Improvements in house design led to the building of chimneys, and the need for iron fire-backs to protect the brickwork. Many Wealden farmhouses contain examples of these decorative and functional plates. In several Wealden churches there are examples of iron memorials.The oldest is in Burwash, dating from the 1530s, while Wadhurst church has over 30, dating from the early-17th to the late-18th centuries.
As competition from imported iron increased, the Wealden ironmasters began to concentrate increasingly on gun founding, and examples can be found all over the world, wherever Britain fought or traded. Eventually, the onset of the Industrial Revolution took heavy industry north to the coalfields, and the last furnace in the Weald, at Ashburnham, closed in 1813.
Waiting to be revealed
So, where are the remains of iron production? Building stone was too valuable in the Weald to be left unused, so the works were dismantled, and the woods grew back over the former sites. Only the telltale waste, called slag, from the smelting process, and some of the hammer and furnace ponds are left to remind us of a once-great Wealden industry.
Text supplied by Jeremy Hodgkinson of the Wealden Iron Research Group
Trees and woodland are a particularly distinctive feature of the High Weald landscape - with woodland, much of which is classified as ancient, covering over a third of this nationally important landscape.
Many woods are small - treebelts, shaws and small woodland blocks between the medieval field pattern - the remnants of ancient forest cleared by early farmers.
Slow to be cleared
The woods of the High Weald were relatively slow to be cleared because they were a valuable resource: yielding timber for building; fuel for heating and charcoal for iron smelting as well as animal feed - acorns and beech mast for pigs. Although heavily exploited, woods in the High Weald were rarely destroyed and the High Weald remained relatively uncultivated. At Domesday (1086) it was the most densely wooded area remaining in England.
A valuable resource
Even when agricultural clearance did begin in the High Weald, much of the woodland was retained. Field boundaries were formed by clearing spaces within woodland, leaving strips of the original woodland between the fields. The many woods on steep-sided valleys and gills were impossible to clear and farm. The remaining woodland continued to provide valuable resources, particularly for the iron industry.
Over 400 years old
Much of today's High Weald woodland has probably never been cleared. Today, over 70% of the High Weald's woodland is classed as ancient - having been continually wooded since at least 1600AD (nationally, only about 19% of woodland is ancient). Having existed for hundreds of years, ancient woodlands are very important habitats for certain woodland plants that can only colonise very slowly. Ancient woodlands also contain a wealth of archaeological features - for example the remains of iron workings.
Home to rare species
High Weald woodlands were managed for centuries by skilled workers, using a rotational coppice system. This ensured that a renewable supply of wood was always available - especially for charcoal and building materials. Traditional coppicing is an important woodland management technique, creating a unique habitat that has vital biodiversity benefits. Many British flowering plants, mammals and insects thrive under this rotational system - often the rarer species are now only found in working coppice.
The High Weald has many isolated farmsteads, hamlets and dwellings dotted across the countryside.
This characteristic, dispersed settlement pattern, actually supports the highest population of any protected landscape in the UK.
A holiday destination for pigs
The ancient woodland pig pastures of the High Weald - used by farmers from the Downs and coastal plains - were known as dens. These can still be identified and are the key to understanding how the High Weald first became colonized by human settlers - and why it has such a dispersed pattern of settlement today.
As dens were mostly used during the late summer and early autumn, the farmers would have built temporary shelters in which to keep warm while watching their pigs. Over time, the dens became more permanent places of settlement. From then, the first pioneer High Weald farmers began slowly clearing the surrounding woods for animal pastures.
Temporary settlements became permanent
Eventually, the dens became settlements in their own right - either as individual farms or as hamlets - and the isolated, scattered nature of the original dens developed into a pattern of individual farmsteads dotted across the countryside. The survival of ancient dens into modern hamlets and villages is recognisable in the place names - many villages, farms, fields and woodland have names ending in '-den'. Most dens have remained small, but a few have expanded to become larger settlements. Tenterden, for example, means "The den of the men of Thanet". The farmsteads were characterised by a relatively large farmhouse, a large barn and a range of smaller barns , granaries and stock and later oasthouses (used for drying hops) - holding memories of agricultural times and traditions long passed.
This pattern of settlement is very different to Central England, which was settled and communally farmed by large village communities, using shared open-field systems. Villages developed relatively late in the High Weald, again in contrast to much of England: most date from medieval times as centres for trade, not agriculture. Many sprang up around trading points on the high, dry ridge top routes.
Building materials and styles
The traditional building materials and styles of the High Weald are an essential part of the landscape's distinctive character. The building materials have come, in fact, from that very landscape - so it is hardly surprising that they blend in so well. Links with the area's wooded past are evident in the number of timber-framed and weather-boarded buildings, whilst the widespread use of sandstone, bricks and tiles is testimony to the High Weald's underlying geology of sandstone and clay. The building materials have led to a particularly rich architectural heritage of distinctive farm buildings - for example hipped and half hipped barns.
The High Weald countryside gets its ridges, valleys and rolling landscape from the underlying bands of sandstone and clay.
The harder sandstone forms the high land and ridges, which generally run east-west across the High Weald.
The lower land between the sandstone ridges is the result of the softer clays having been more easily eroded.
The action of the elements over time has unevenly eroded these sandstones and clays to leave the steeply ridged and folded countryside that survives today.
Layers of sediment
The sandstones and clays of the High Weald were originally laid down as sandy and muddy sediments.
Starting around 140 million years ago (when dinosaurs still roamed) these sediments formed at the bottom of shallow lakes, or were carried by rivers and deposited on floodplains.
Around 100 million years ago, sea levels rose and the remains of billions of tiny sea creatures then formed another layer of sediment above the sands and muds. Over time, this became chalk.
Uplift and erosion
Around 30 million years ago, massive earth movements began to push all the compacted layers of sediment up, creating a giant, chalk-covered dome.
Over time, water eroded most of the chalk away, revealing the older sandstones and clays beneath - the High and Low Weald. The chalk at the edges of the dome has remained - forming the North and South Downs.
Rock outcrops and gills
The hardest areas of sandstone now form the distinctive sandrock outcrops of the High Weald. In addition, fast-flowing streams have carved out characteristic, steep-sided ravines called gills in the steep sides of the sandstone ridges.
The porous, moisture-holding sandrock and sheltered, damp gills provide ideal living conditions for ferns, mosses, liverworts and lichens. Many of these species are more characteristic of the mild and humid oceanic climate of Wales and Cornwall than that of the South East. Most famous is the tiny, and extremely rare, Tunbridge Filmy-fern.
The High Weald has a unique, radiating network of ancient routeways and tracks. These routes were first formed when early settlers from the surrounding lands began to exploit the area's woods as a seasonal source of food for their animals: for, as well as timber and fuel, the woods held another important resource - acorns!
A tasty treat
Domesticated pigs, being descended from wild boar, enjoyed acorns as a natural food. From as far back as the Neolithic period (c.4300 - 1400BC) or even earlier, farmers from the South Downs, North Downs and coastal plains would drive their pigs into the woods each year to fatten them on acorns and beech mast. This happened in late summer or early autumn and is known as pannage.
A stronghold for pigs
The Weald was the stronghold of pannage in Britain. In 1086 - when the practice was already past its peak - Domesday records indicate that around 150,000 pigs would have been driven to and from the woods of the High and Low Weald!
Farmers from a particular village returned with their pigs to the same woodland place year after year. These woodland pig pastures were called dens.
A legacy of north/south roads, lanes and paths
The frequent passage of pigs being driven to and from the dens formed tracks known as droves, connecting the dens to their parent villages - often as much as 20 miles away. Over time the dens became settlements in their own right, and the roughly north-south droving routes remained, and can be seen today in the pattern of lanes, bridleways and footpaths radiating away from the High Weald.
Centuries of use by many trotters, feet, hooves - and, later, cartwheels - have worn the soft ground away so that, today, many of the routes have deeply sunken sections. In spring and summer, the High Weald's narrow, sunken lanes with their ancient, wooded banks are transformed into shady 'tree tunnels'. Many are lined in places with wildflower-rich verges, important wildlife refuges - some even designated as 'Roadside Nature Reserves'.