Our exploration of the hidden qualities of hornbeam continue with a look at its presence in three English woods.
HORNBEAM is a thoroughbred native tree generally regarded as a nondescript entity because it has been left behind, consigned to the mid-storey and understorey as coppice or pollards. Unless the observer explores the woodland and views its component species close up, he or she might not even know hornbeam is there.
This is because hornbeam was historically not allowed to assume full tree potential either in forestry or the amenity landscape, though when given the chance it embarks on a sure and steady growth path into a sturdy standard tree, albeit at a relatively slow rate, to eventually vie with the best of the rest at the climax of the canopy. Even less well known and appreciated is hornbeam’s largely unexploited potential as a versatile addition to amenity and landscape planting as standards, tastefully designed pollards, as pure hornbeam hedges and even for topiary.
HORNBEAM’S TRADITIONAL ROLE
Hornbeam is only generally well known on the eastern side of southern England, which the tree managed to colonise following the species’ late arrival after the last ice age and before the sea inundated the land bridge between what is now mainland Europe and Britain. Even here, hornbeam gives the impression of both a tree and timber well past its time, existing almost entirely of ageless coppice which for the most part is well over-stood.
Hornbeam remains hidden away in the understorey, where it is not put to best use.
There is nothing uniform about the structure of hornbeam trees, which have been cut as either pollards or coppice (or both), often multiple times over the centuries and at different heights. The net result is a collection of over-stood hornbeam pollard and coppice woodland which in winter condition portrays the spookiest of all English woodland, reminding me of scenes from the film Sleepy Hollow with Johnny Depp. My neck of the woods (Hertfordshire, Essex and the old county of Middlesex) is still plastered with hornbeam coppice, so the tree obviously had its uses in centuries past.
In stark contrast to lime (Tilia), one of the softest and lightest of hardwoods, which historically paid the penalty for its condition, hornbeam is at the other end of the wood workability spectrum. Lime trees were easy to fell and the wood easy to work using rudimentary tools one of the reasons why our native limes (small-leaved and large-leaved) are now relatively rare, having once covered the country as pure lime woods.
Hornbeam, on the other hand, is notoriously heavy, hard and resilient even by hardwood standards, with the timber finding few fabrications outside of situations where only the heaviest and hardest of hard woods would do – chopping blocks, tool handles, yokes for livestock, plough blades, etc.
However, hornbeam had another use and a vital one too, for which no other native hardwood could come anywhere near its attributes. Hornbeam was a number-one fuelwood for south-east England, being used to heat homes and fire the furnaces.
COMPARATIVE HEAVINESS AND HARDNESS
A comparison of European hornbeam (Carpinus betulus) and European lime (Tilia x europaea) at, respectively, the top and bottom ends of the scales for heaviness and hardness, using several parameters well established in the timber and woodworking industries, shows how hornbeam is head and shoulders above other British native hardwoods.
According to a snapshot comparison by the Wood Database, European hornbeam weighs in with an average dried weight of 735 kg/m³ (46 Ib/ft²), Janka hardness at 1,630 lb (7,260 N), modulus of rupture 16,010 lb/in² (110.4 MPa) and a crushing strength of 7,320 lb/in² (50.5 MPa).
READ PART I: Hornbeam – hard as horn, hot as coals
Common lime cannot boast such a portfolio of heavyweight credentials. Corresponding values for European lime come in at: average dried weight 535 kg/m³ (33 lb/ft²); Janka hardness 700 lb (3,000 N); modulus of rupture 12,380 lb/in² (85.4 MPa) and crushing strength 6,500 lb/in² (44.8 MPa).
The Janka hardness test, which was created by the Austrian-born, North American scientist Gabriel Janka (1864–1932), measures the resistance of a sample of wood to denting and wear. Modulus of rupture, sometimes referred to as ‘bending strength’, is a measure of a wood specimen’s strength prior to rupture. Crushing strength, also known as ‘compression strength parallel to the wood grain’ is a measurement of the wood’s maximum crushing strength when pressure is applied to the ends of the wood samples, i.e. compression parallel to the wood grain.
HORNBEAM – UPSTAIRS OR DOWNSTAIRS TREE
When it comes to cutting and tree canopy structure, none is more versatile than hornbeam. Though relatively rare, hornbeam does exist in woodland as a maiden tree, which in forestry is defined as a tree of seedling origin which has never been radically and routinely cut by coppicing or pollarding. The result is a standard, defined as a tree with a single stem and a clear trunk at least 1.8 m (6 ft) in height.
The word ‘coppice’ can be used as a verb to describe the cutting back of a tree or shrub to ground level to form a stool from which new shoots, called ‘spring’, is stimulated to grow. It is also used as a noun to describe the resulting new growth, which may be coppiced again on an established cycle, according to the species. Or it will be allowed to continue growing and referred to as over-stood coppice. Likewise, ‘pollard’ describes how the top of a young tree is cut back to the trunk to promote a dense head of foliage, which means that, in time, the specimen becomes a multi-stem tree.
All that sounds simple enough, but not so, because it all depends at what age a tree is cut, the height at which it is cut, and whether cutting continues periodically over the centuries. Hornbeam is probably the most complex of all the tree species traditionally subject to pollarding and/or coppicing, but by the same token is the most versatile and open to cutting. That makes woodland hornbeam the most varied and variable of trees in this respect – height, branching and canopy structure.
There is still a considerable amount of hornbeam spread across the northern reaches of London. Much is now within the boundaries of Greater London, in outer boroughs like Hillingdon, Harrow, Barnet and Enfield, into Hertfordshire and way out east into Essex.
The roots of this woodland, in relation to the current structure, state and condition of the hornbeam tree, are roots firmly embedded in social history. Its form and structure depends on whether the trees were traditionally cut by local communities, mainly for firewood and fuel, by coppicing and/or pollarding and when this traditional way of life ceased. Or in some cases, though relatively rare, where landowners forbade local communities from taking wood and timber, which means the hornbeam trees now stand proud as standard trees, up with the rest including oak and ash standards.
Three of the biggest woodlands spread across the outer North London boroughs and the adjoining Home Counties in which hornbeam is a significant component species illustrate these differences. From west to east, these woodlands are Ruislip Woods, Hadley Common (Hadley Woods) and Epping Forest.
RUISLIP WOODS
Ruislip Woods is a ancient semi-natural woodland covering 294 hectares of what was once in the County of Middlesex, but is now within the London Borough of Hillingdon.
Comprising Bayhurst Wood, Copse Wood, Mad Bess Wood and Park Wood, Ruislip Woods has since 1947 been a site of special scientific interest (SSSI), containing substantial areas of native English oak standards over hornbeam, the latter rigorously coppiced for over 500 years until the 1930s, when the practice stopped. In 1982, a 30-year-old arborist called Colin Chambers arrived to take up the position of trees and woodland officer at the London Borough of Hillingdon. According to a well-designed plan, rehabilitation of the hornbeam coppice, now grossly over-stood, got under way. In 2019, I accompanied Colin when he returned to Ruislip Woods after a gap of 20 years to see what had happened, recounted in Forestry Journal.
Colin explained how the traditional centuries-old way of cutting in Ruislip Woods was not classic coppicing at ground level, but neither was it pollarding. The last cut backs, which took place in the 1930s, had not taken place at ground level, but one to two feet from the ground, leaving a short stump or leg from which subsequent sprouting had occurred. Colin surmised this was a convenient height for billhook use. He went on to explain how in 1982 they were faced with three to five massive over-stood stems per stool, representing 50 years of growth.
He said: “To begin with we did not revert to the traditional system, but selected out and saved the strongest and straightest pole or waver and cut the remainder at the previous coppice cut.” Nearly four decades later, I could see the net effect of this singling approach as conversion to high forest.
HADLEY COMMON
Hornbeam has most commonly been treated as a coppiced understorey tree rather than a standard, upper-storey tree, making high hornbeam forests a rarity in England. I have only come across it once, in Hadley Common (called Hadley Woods by the locals), located entirely within North London, considerably smaller than Ruislip Woods but in its own way just as interesting. Occupying 72 hectares and spread across the London Boroughs of Barnet and Enfield, this mostly wooded area is that portion of the Enfield Chase Forest assigned to Monken Hadley when ‘The Chase’ was finally enclosed in 1777. Oliver Rackham said Hadley Common represented the last authentic two per cent of the Enfield Chase.
Archives indicate that pre-enclosure, local communities were allowed to collect firewood and fuel and graze their animals on this land. However, the structure of the woodland indicates this all changed after enclosure, as well as the area undergoing clear-felling and organised replanting. Despite Hadley Common’s ancient woodland status being beyond doubt, it is difficult to find living trees which pre-date the late 18th century. The main tree species, clearly those which were planted, are oak, ash, beech and hornbeam. The hornbeam, concentrated in particular areas, is entirely of standard trees, the size of which now matches the other high-forest tree species.
EPPING FOREST
Epping Forest straddles 2,400 hectares of land to the north-east of London where the London Borough of Waltham Forest meets and merges with the County of Essex. Its iconic hornbeam is different again to that of Ruislip Woods and Hadley Common. Like much of the beech and oak, hornbeam in Epping Forest was cut as pollards for many centuries, stopping abruptly in 1878, though grazing of cattle and ponies continued well into the 20th century. Today’s tree form and structure reflects this history and culture, with Epping Forest containing some of the most amazing ancient hornbeam pollards in the country.
Epping Forest is ecologically diverse, with areas of woodland, grassland, heath, streams, bogs and ponds. Its elevation and thin, gravelly soil, which is the result of glaciation, historically made it much less suitable for agriculture than surrounding areas of the County of Essex. As a consequence, Epping Forest was historically managed as a common, the land being held by a number of local landowners who exercised their economic rights over such aspects as the cutting and extraction of timber.
Commoners had a collection of rights, which included the right to graze animals, to gather foodstuffs and to turn out pigs to eat mast, which in this instance would have been primarily acorns and beech nuts. They also had the right to collect wood for fuel and other uses. Hornbeam would almost certainly have been the major source of fuel and firewood. Epping Forest was designated as a royal forest during the reign of King Henry II in the 12th century, which meant the monarch was the sole person with the legal right to hunt deer.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here