Background to Coppicing - a brief history
by Edward Mills FICFor
Director, Cumbria Woodlands
revised version contributed 2006
Coppicing has been traced back to Neolithic times by archaeologists who have excavated wooden tracks over boggy ground made entirely of coppiced material. There are also written records, going back to at least 1251, which describe the value and type of material cut for woods in East Anglia. Coppicing can provide a constant supply of material for a wide variety of uses. The material is of a size which is easily handled. This was very important before machinery was developed for cutting and transporting large timber, when anything more than 20 miles from a large river could only be used locally. Through the 18th and 19th centuries, coppiced woodlands provided industrial charcoal for the smelting of iron and bark from which tanning liquors were prepared. However, by the mid-twentieth century coppicing was in rapid decline and many coppice woods were replanted with conifers, or simply neglected.
Coppicing occurs when a tree is felled and sprouts arise from the cut stump (known as a stool). This process can be carried out over and over again and is sustainable over several hundred years at least, the stool getting ever larger in diameter. The shoots arise from dormant buds on the side of the stool or from adventitious buds developing in the cambial layer below the bark. Root buds can produce coppice shoots when close to the stump, especially in birch and hazel. The development of the buds is initiated by a change in plant hormone levels following removal of the crown or stem.
Species and growth
All broadleaves coppice but some are stronger than others. The strongest are ash, hazel, oak, sweet chestnut and lime whilst the weakest include beech, wild cherry and poplar. Most conifers do not coppice, one exception being yew. The number of shoots per stool depends on the species, its age and size. A large number emerge in the first year - up to 150 in some cases, but these quickly die off in following years as self-thinning takes place. By mid rotation 5-15 are left. The final number depends on the rotation length and species. Sweet chestnut coppice cut in its 16th year has about 5,000 stems/ha. Oak, hazel and lime commonly grow a metre in their first year; ash and willow can grow much more and in the second year growth is generally greater. From the third year, growth slows dramatically.
Depends on the rotation length, site and species. Indicative yields are as follows :-
Oak 2-4 tonnes per hectare per year over a 30 year rotation
Sweet chestnut up to 10 tonnes/ha/yr over a 15 yr rotation
Mixed species 3-5 tonnes/ha/yr, or 45-75 tonnes at year 15 and 90-115 tonnes at year 30
Hazel 25 tonnes/ha at year 10 of a rotation
Oak and ash usually grown on a 25-35 year rotation:- 200-500 stems/ha
Sweet chestnut usually grown on a 15 year rotation:- 8000-1000 stems/ha
Hazel usually grown on a 7-10 year rotation:- 1500-2000 stems/ha
Usually established on a new site as per a normal plantation and then cut back at year 3 or 4 to begin growing a new crop.
Organisation and Systems of Working
Coppice is normally divided into coupes (otherwise known as a fell, a cant, a hagg or, more simply, a compartment). If cutting neglected coppice, it is usual to cut the most neglected areas first, but if usable material is required straight away, some better coppice will need to be cut as well. As a rule of thumb, coupes should be at least 0.5 ha in size. However, the UK Woodland Assurance Scheme (UKWAS) certification standard states that no more than 10% of semi-natural woodlands over 10 ha in size should be felled in any 5-year period. This does not necessarily constitute sound advice if you wish to bring a large coppice woodland back into management rapidly. Large coupes have the advantage of deterring deer from entering.
There are two systems - coppice and coppice with standards. The former has no standard or maiden trees (i.e. no trees which are not coppiced). The coppice with standards system is much more common. Oak normally makes up the standard trees but they could consist of ash or, less commonly, birch. Standards should be retained at a density of about 30-100 per ha (a 10-18m spacing), and should consist of a variety of age ranges. Try to leave a few of the very oldest trees to grow on to become veteran trees. If there are no standard or prospective standard trees available, its best not to try to create standards from trees that might blow over such as willow, or by singling trees from coppice, as these may also be unstable. It is probably better to leave a space in which a new standard might develop naturally during the rotation. Up to 40% of the canopy can be occupied by standards, though it is generally lower than this. When coppicing, look out for seedlings to protect and allow to grow on to form standards. Too many standards retained will result in poor coppice regrowth due to insufficient light reaching the ground.
A sloping cut is traditional as it was thought to shed water and prevent fungal decay. However, there is no evidence that a sloping cut minimises fungal attack.
A low cut maximises the yield and encourages shoots to develop their own roots; it is also safer to work when stumps are cut low. However, if cuts are made too low, especially on old stools, most of the material that is vigorous enough to produce new shoots will be removed and there is a significant risk of reducing the vigour of the stool. Cutting too low also removes much of the deadwood and other interesting habitat that often lies at the base of old coppice stools. The bark below the cut should not be damaged.
Work traditionally takes place during the winter - October to the end of March. Coppicing of oak in order to supply bark for the tanning industry traditionally took place during May and June when the sap was running. There is no silvicultural reason for coppicing in the winter months, but coppice which is cut during July, August and September, will produce shoots which are not frost hardy. Coppicing during the spring will disturb nesting birds and trample the ground flora. Bluebells in particular are thought to be sensitive to excessive trampling. Coppice material cut in the winter works better and lasts longer than that cut when the sap levels are higher.
In many parts of the country, including Cumbria, the deer population is usually too high to risk coppicing without suitable protection from browsing. There are many options for protecting coppice regrowth against browsing damage by deer, and successful protection may lie in a combination of techniques:-