Nature 2009 April

In celebration of the beech!

If the Chiltern Hills has but one signature feature it is the beechwoods. The topography, height and overall poorer fertility of the Chiltern soil has set apart this upland area from other similar ones in southern Britain, such as the Cotswolds, with their rich sheep pastures, or the Oxfordshire and Wiltshire Downs with their sheep folds.

The history of the Chiltern beechwoods is a long one but is cut short here. The last Ice Age sculptured the Chilterns as we see them today. It took until around 8000 years ago, 2000 more years than oak, for mature beech forests to emerge, spawned from pollen blown across the joined-up continental land mass soon to be split by the English Channel. Since then, there have been successive clearance and envelopment by the ancient Wildwoods before being finally ‘tamed’ by axe-wielding Stone Age man around 2-3000 years ago. Without continuous human intervention, these hills would not have the patchwork of managed woodlands, open pasture or arable land we have inherited today. Instead, a mixture of wildwood or impenetrable scrub would have persisted until probably the 16th century and the typical Chiltern villages we live in today would either never have emerged or would not have uniquely developed around or along open common land as they have.

Unlike today, in medieval times a stand of beeches would not have stretched half way to the sky. Instead, trees may have been pollarded or coppiced and if allowed to grow upwards at all would certainly not have been left intact into late middle age or allowed to grow lanky trunks topped out by a broad tree canopy. If oak provided the early settlers to this hilltop region with building materials, beech supplied the energy source domestically and industrially (for smelting iron). From the 16th century, beech’s value as firewood was such that it could be felled and profitably transported from the Chilterns by barge to London.

The next dramatic change came in the 17th century when the first plantations of beech appeared in the Chilterns to support the demand for wooden furniture. Writers of the time, such as Gilbert White, were able to describe both the gnarled and unblemished barked versions of beech growing alongside each other, debating in letters to each other their preferences either for ‘smooth rind’ or ‘knobbed and studded’ versions.

Wood pasture, an almost forgotten farming method these days, was an essential part of this overall woodland management, right through from the early middle-ages, with animals let loose to graze in the autumn off the beech mast. A wood was valued and taxed according to its ‘hidage’ which equated to the number of swine or other domesticated animals that could be supported therein. Look out for clues remaining today of this historic woodland use, such as banks and ditches on wood edges: some still with the remains of coppice and hedging which was once regularly maintained to pen in the grazing animals.

Stepping back and thinking how a woodland was (and is) used also unlocks the key to the wildlife that has been attracted and sustained historically. For example, the robin has always been an opportunist bird. The use of woodland to turn out pigs or forests to sustain wild boar for hunting led to the robin following the swine around, even perching on its back whilst the animal turned the soil in search of roots and bulbs but also unearthing worms and insects for the bird. Fallow deer were introduced by the Romans for hunting and would have been penned in certain areas. Pheasants have been introduced to our woodlands several times and eventually led to the elimination of polecat and martens. Beaver were commonplace until the middle ages when their activities came fatally into conflict with man. Even red squirrels were introduced to hardwoods in the middle ages and were prized for their fur. Their natural habitat were the coniferous forests where they have since retreated: following introduction of the grey squirrel from America in the 19th century, which in turn severely damages the bark of beech trees. Both Muntjac and Glis glis have similar dark histories.

The demise of oak trees and coppiced beech woods, replaced by plantations of smooth-barked beech, has also eliminated many species of moss, liverwort and lichen from the beech woodland scene. The close canopy has starved the woodland floor of light but this has provided an ideal habitat for the early flowering bluebells which so uplifts the spirit each Spring.

With the timber industry no longer supporting the management of woodland resources, protection of beechwoods as Chiltern heritage is important. Conservation organsations (eg the NT) and local people purchasing a woodland at risk from exploitation, are vital for the protection of local woodlands. But there are other risks too. In an ancient woodland, a healthy beech tree might live up to 250 years. Plantation stands of beech now well over 100 years of age are already well past their ‘fell-by’ dates. Hitherto, the trees would have been cleared and replanted after 40 to 50 years. Grown close together on shallow, well drained soils or on hillsides, many are unlikely to survive into old age. On a walk in the woods today you are quite likely to come across an upended tree. The clues to its demise are the overstretched shank (trunk) which has grown fast and spindly as it struggled against its neighbours for light. A second clue is the huge haunches or plates which the tree has been forced to enlarge to buttress the trunk at ground level. Eventually, either unable to support its own weight or, as average annual temperatures increase and the water table falls, becoming ‘stressed’ through not being able to draw sufficient nutrient, it will all the more likely succumb to a gale. In their lingering death and afterwards they provide more sustenance to flora (fungi and bacteria) and fauna (beetles, wood lice and millipedes) than perhaps they ever did in life.

The latest threat to our oaks and beeches, reported in the last 12 months, is from a fungal disease spread via rhododendrons, which are frequent escapees into woodland from parks and estates, including our own local invasion in Drayton Woods. There are plans being prepared nationally to remove rhododendrons in such locations to stem the increase in sudden death of wood and parkland beech and oak.

Victorians viewed beeches as elegant landscape trees: ornaments to show off an estate’s features across open countryside. Elegant tree cathedrals sprang up. Beeches were planted to adorn ancient landmarks such as our own Cholesbury Hillfort. Sadly, as all these trees were planted at once, there is no succession and a walk around the ramparts will reveal time is already taking its toll. A visitor returning in less than 30 years will no doubt do so to a very different scene. So get out there and enjoy the beechwoods and the wildlife therein while you can. They may not be around for much longer!

No weather notes this time by the way. There was just far too much of it in February: making no further mention seems the decent thing to do!