Draft:Coppicing: A dictionary of words and terms

Little information exists on precise definitions used in discussions about coppice. Definitions of individual terms do exist (such as in the glossary of ‘Woodlands, A Practical Handbook; British Trust for Conservation Volunteers, September 1980) but are scattered and like the publication cited, often obscure. Some of what can be found is contradictory. There is also some geographical variation in usage of terms.

Often it would be handy to have a set of definitions to prevent the frequent misunderstandings which occur when talking ‘coppice’. So, for your consideration (and hopefully comments) here is a list of terms that one old ecologist/woodland manager currently uses in the context of hazel coppice with oak standards managed with biodiversity as a significant part of the overall rationale of management.  Kind of alphabetical but related terms are grouped together. At least for this draft. References are to be added – this draft is created by downloading my head

Terms still requiring inclusion and definition.

Veteran (tree) characteristics.

UK native oaks both spp.

Veteran tree

Assart

Tanbark Until the advent of chemical leather tanning using chromium after 1840, oak bark was the primary source of the tannins used, and long-rotation oak coppice was a major source of the bark.

Coppice with standards: coppice managed and cut as a main crop with larger trees (often oak for hazel coppice) as a much longer Rotation secondary crop. See Standards. Traditionally, standards were imposed on coppice by institutional and royal/major landowners to fill needs for large timbers for shipbuilding and prestige construction. Each standard casts shade under its Canopy which will suppress growing coppice in the area of shade. See Plain coppice.

Standards:  Oak trees intended for eventual cropping as timber. Should be a range of ages and sizes approaching maturity and in maturity. See ’12 per Acre’. If it’s big enough to cleave into 4 Sussex rails or two uprights it’s a standard.

Waivers: Young oak trees (older than seedlings or saplings) that may become standards in due turn. Or may be cut before becoming standards. If you can get both hands around it at breast height but can’t get 4 Sussex fence rails out of the first 10’, it’s a waiver. See ’12 per acre’.

Conservation trees: Oak standards that will not be felled due to high conservation value. Holes, dead wood, lack of timber value, prominent siting, etc. Are often trees that have survived because they weren't worth the bother of felling due to large size or significant flaws or both.

OR:                                Larger trees of other species such as ash, field maple, cherry chosen for retention as large trees. Similar for sweet chestnut, beech, sycamore, wild type crabapple, hawthorn and historical artifacts such as relict plantation trees in former plantationised woodlands re-converted to hardwoods with coppice, boundary pollards or coppards on assart boundaries, etc.

Canopy trees:  Large trees in a coppiced woodland run for biodiversity as an important goal and of species other than oak (see Standards) which are earmerked for retention above or adjacent to (casting shade over) coppice. Note overlap with ‘conservation trees’. Each conservation tree or canopy tree should count as one of ’12 per acre’. Note this is a modern usage. Formerly if a large tree not an oak could be profitably felled with the landowner’s permission, down it would come. BUT, standards in traditional coppice could be of species other than oak at need.

Canopy: A tree’s leaves and branches, which when leaves are on, casts an area of shade. Canopy spread and density of a tree left uncut can fluctuate during its life, increasing as it grows, reducing in periods of hardship or (especially older oaks) retrenchment and increasing again in recovery. The outer edge of the canopy is often termed the drip line. The canopy spread of an open-grown tree (or a standard spreading above hazel subcanopy) will be much larger than that of trees of the same species growing up together in a high forest context. The idea that a tree's roots spread only to the canopy edge is a myth.

Maiden: A tree that has never been coppiced, stobbed/copparded or pollarded, pleached or otherwise regrown after being cut or pollarded. Typically a single stem or trunk supporting a crown of branches.

Pollard: a tree deliberately cut high on a main trunk in the expectation that it will re-grow. Started from a young tree and then re-cut at intervals. The initial cut was made well above the browse height of cattle who will grab drooping branch ends, eating along them and breaking them off as they go. Indicative in pre-industrial times of the immense pressure to maximise grazing land whilst retaining a source of small timber or poles. Often pollard branches had uses as tree hay cut and stored for winter use or could be dropped as extra fodder (and used as fuel after stock had eaten branch tips and bark). Oak, ash, lime, poplar, willow (especially crack willow) and others. Holly, especially New Forest where groups of pollarded hollies were known as hollins. (Yorks dialect name for holly and note that in some areas a holly would be planted in a hedgerow to mark a joining water course, spring or field drain outlet and sometimes later retained as a pollard. See Bolling.

Lapsed pollard: a pollard long out of management. Lapsed oaks, especially can be huge with very wide trunks and tree-sized stems from the top of the Bolling. It is often mistakenly assumed that oak pollards were meant to be cut for large timber. However it must be remembered that although the Romans and Saxons had saws, they were tools for prestige work and woodmanship would have been done with swung tools with axes used for larger felling. The logistics of using an axe in a pollard to cut stems is frightening and an indication of the pressures leading to the creation of pollards as well as a very strong indication that pollard stems would have been cut at small diameter. Most pollards now extant are long-lapsed, especially oak and may be much older than maiden trees of similar girth as each pollarding is an ‘insult’, slowing rate of expansion of girth.

High pollard (or amenity pollard): Modern amenity treatment of a street tree (especially) aimed at retaining the tree whilst restricting  its growth and root spread (and root damage of paved areas). Cuts are made on branches (low in a canopy) and then re-cut at frequent intervals to avoid branch shed due to mass buildup at the end of a branch which may be hollow due to rot ingress. The reader is invited to read up on Alex Shigo’s ‘compartmentalisation theory of wound response in trees’ and note that hid for of pollarding started on the branches of a well-established tree (c.v. pollard) bypasses several compartments implicated in wound response. Crown reduction is different again and is a modern arboricultural practice not covered in this work).

Coppard/stob-cut. Low-cut ‘pollard’ often cut at shoulder or hedge height and often in a hedge line where the hedge would give some protection from cattle browse damage. Many species but often oak.

Stag-headed (base). Base of a tree that has formerly been coppiced but where coppicing is now lapsed. Shows old branch/stem scars and swelling and trees may be double or triple stemmed. There may be rot-holes in the base of the tree. Tree may be self-singled and may be large.

Stag-headed (crown). A tree (often oak) which has undergone dieback in the crown leaving bare branch cores of rot-resistant heartwood amongst the living crown.  See Retrenchment Growth.

Stem: a trunk on a tree, usually slender. Mayb be single or multiple.

   OR: a single upright growth of many on a coppice stool (or pollard/coppard).

Stool: A tree that has been coppiced, usually many times. Multi-stemmed arising from a +- spreading base. See Stag-headed (base). Stools in ancient woodland (hazel especially) may be far older than the visible growth. See Stool Expansion and Stool Contraction.

Bolling: The upper end of the trunk of a pollard, swollen by stem and branch scars form previous pollard cuts. If a pollard dies and is ‘hulked’ (stems removed to render the main trunk stable) and the sapwood is left to rot in situ, the heartwood at the bolling may be revealed as a wonderful complicated puggled mass of twisted grain and subsumed epicormic growth having arisen over centuries.

‘Bluebell cycle’: Informal, neollogism. Bluebell is an archetype of British Isles woodlands. Not entirely confined to woodlands, it can be planted and appears in hedgerows (especially old ones) and in old pasture where competition from tall grasses is reduced for environmental reasons. Does well under derelict hazel and areas with canopy tree cover, coming into ‘the green’, growing and flowering before tree leaf-out and then setting seed and ‘disappearing’ in early summer. Can make a stunning display of blue. Bluebells are unpalatable to deer and remain un-grazed but note that muntjac will root (as will boar) and kill or dramatically reduce bluebell densities. Under in-cycle coppice, bluebell ‘cycles’: flushing when the coppice is cut and then cycling down as shade cast by the growing coppice increases as the hazel sub-canopy closes over. At this stage bluebell will often be seen in ‘the green’ in spring and early summer if searched for and when it flowers, the flowers will be fewer as shade increases and less easy to see. Individual plants may not flower. When coppice is re-cut, bluebells flush again. A similar ‘cycle’ affects other woodland ground flora. See  Bramble cycle.

Bramble cycle: Informal, neollogism. Many woodlands have populations of bramble, which persist at a low level under dense shade. Bramble may ‘flush’, after coppice restoration, especially where significant ground disturbance accompanies coppice cutting but in quality, high density coppice, bramble densities are decreased by developing shade and decrease as the coppice grows, becoming low by the time the coppice is ready to re-cut. Deer browsing can exacerbate bramble density and obtrusiveness. This occurs due to two reasons: Repeated browsing-out of bramble growing tips encourages branching and ‘thorniness’, increasing density of bramble stands.

  Deer browsing of regrowing coppice extends the time needed for the developing hazel subcanopy to close over. Canopy closure suppresses bramble growth by shading, so increasing time to subcanopy closure increases bramble quantity and density.

Bramble increase is sometimes seen as a reason not to restore coppice. A decision not to restore for this as a primary or major reason is questionable. Bramble is a major nectar source and important as insect bird and small mammal food and as bird nesting cover.

Ancient Woodland: In the UK, a woodland that has existed since 1600 or before. The date of 1600 is chosen because around this time rural populations increased dramatically and the run-up to the Industrial Revolution accelerated. This meant that the pace of change in rural areas increased dramatically and the chances of the biota associated with old woodland habitats became increasingly less likely to spread from extant woodlands into new ones decreased radically. See Ancient woodland indicator.

Ancient woodland indicator: Herbaceous plant, tree or shrub that tends to grow in ancient woodlands. Typically have poor powers of long-distance distribution, are sensitive to ground disturbance and may not reproduce readily from seed. In the UK there are regional, often county-based lists of such species. Such species, when occurring in a context of several species form the same list, signs of former working of trees (stag heading (base) stool, coppard) and certain archaeological remains can comprise an accurate signpost towards a woodland being ancient woodland.

Bonfire: Fire used to dispose of unusable material in worked coppice. For in-cycle coppice, these will be small and scattered through larger worked areas. As such they will have small impact on the ground below and may provide short term niches for specialised mosses, fungi and other species. Traditionally, bonfires were often required to leave worked coppice clear of obstructions and litter.  Old woodsmen often sited bonfires under standard canopy edges to ‘chase up’ the canopy, reducing shade on the coppice whilst not damaging the trunk (which would attract censure from the woodland owner or their agent). Woodsmen, paying for the Standing Crop would not benefit from standards and would suffer a reduction in quality and quantity of the coppice crop through canopy shading).  From a nature conservation point of view, large, long-lasting and very hot fires require caution as localised damage to soil structure and fungal mycelia. However, the practice on some sites of siting bonfires on raised steel and timber platforms and then removing all ash from site has limited evidence for its necessity.

Comfort fire: Small fire used by woodland workers to keep chill at bay while working in winter woods. Can be used to make tea, warm hands, dry clothes. Term can be derogatory when used by (often younger) employers pushing for ever-greater productivity.

Charcoal:  High quality, light weight fuel produced by heating wood (or other organic material) with restricted access to oxygen to drive off all water and volatile compounds leaving a black, carbon-rich residue of high fuel value and capable of burning in forced air to reach high temperatures (>1000⁰C) for working and smelting steel and other metals with use dating back around 5000 years in the UK archaeological record but much further elsewhere. Around 8 tonnes of seasoned wood are needed to produce 1 tonne of charcoal. Temperatures reachable with charcoal are much higher than can be reached with wood as fuel and use less mass of fuel. Traditionally made in an earth clamp using part of the charge to drive the process and more recently in a steel ring kiln. The trick is to run the process long enough to maximise charcoal produced and minimise the amount of charge used to drive the process.  Modern processes heat wood in a closed retort from the outside. The retort can have taps for the removal of wood gas (can be used as fuel and to drive internal combustion engines) and tars (multiple uses). Charcoal once fuelled all metalworking (with evidence dating back many thousands of years) and other high temperature industrial processes (see white coal) but scarcity led to the eventual adoption of coal as the primary fuel. This accelerated after the discovery of coke (coke heated in limited oxygen) in the 18^th century and leading to a crash in UK charcoal production in the century thereafter. Notably, scarcity of charcoal for industrial processes actually led to the survival of large areas of woodland in the weald of Kent and the Sussexes as these were jealously guarded by Roman ironmasters and later by Medieval ironmasters.

Charcoal was also an essential component of gunpowder, with certain woods such as alder producing high-purity, friable charcoal necessary for the production of high quality black powder for firearms and ordnance uses. Activated charcoal for gas masks in WW2 took large quantities of UK charcoal.  This web page is informative: http://www.weyriver.co.uk/theriver/industry_6_charcoal.htm Charcoal hearths in woodlands are indications of ancient status (in context).

White coal: fuel used in lead smelting and working in England from the mid sixteenth to late 17^th centuries and produced by heating chopped wood to drive off all moisture but retaining the majority of volatiles. Burns at a lower temperature than charcoal and cleaner and more reliably than ‘raw’ air-dried wood. Used to prevent lead evaporating. Could be used mixed with charcoal in other processes. Was produced in Q-pits, distinctive circular pits with a channel often found in south Yorkshire woodlands and recorded from the Mendips.

Cordwood: Material big-enough-diameter-for-firewood cut in uniform straight-as-possible lengths (4’ traditionally), tight-snedded  and stacked in a cord for extraction at a later date. Often sold by the cord traditionally. Often not cut in uniform lengths, or straight or snedded these days, compounding difficulties of extraction and processing. See Habitat piles and Fuelwood.

Coppice enrichment: Interplanting extant hazel coppice with young hazels to reduce stool separation and increase number of stools per acre. Can also include layering hazel stems to create new stools. If saplings are planted in short tree tubes and deer are present, a varying proportion of planted trees may be browsed and killed. If long tubes are used, planted trees may be killed due to shading: Shading from coppice regrowth plus shading effect of tubes (and from canopy trees: ‘gaps’ to be infilled may be larger under canopies). If the whole cant is fenced and especially if the 7-year cut is missed, new plantings can fail and die simply from shading. See ‘Grant farming’).

Cycling down: The process by which hazel stools, usually in derelict or long-overstood coppice suffers reduction in stem count, diminution of stool size and diminution in stool density due to stool contraction of which increasing competition and canopy shading is a major contributing factor. See Stool Expansion.

In-rotation coppice: Hazel cut every 5-7(8) years.

Dead Hedges: See Habitat piles. Enclosures created to exclude deer access to re-growing coppice in an entire cant to aid regeneration. (Does not include ‘protecting’ individual stools with brash). If high enough (6-8’) and dense enough (needs to be very dense) can work very well if an area of derelict hazel is cut for firewood (all unused material goes in the dead hedge) or an area of overstood deer-damaged coppice is cut to restore (all material goes in the hedge). Excellent as small bird nesting and foraging cover, especially of there is bramble growth and hedges join up allowing small birds to enter away from nest sites and make their way under cover, so avoiding the attention of predators. Last 3-5 years and then become permeable for deer. A one-shot tactic as at 7 years there is not enough material to re-place the dead hedge as an effective deer barrier even if all cut stems are used in the hedge. If product is maximised and no other protection method is used, (deer fencing) stool damage or widespread death of stools can result.

Deer fence: Permanent and maintained 6-8’ fence to exclude deer from areas of coppice. Effective. Expensive. Obtrusive. Exclusive (of free and open public access) on ‘open’ sites. Also protects ground flora.  Limited life dependant on material used for strainer posts and intermediate. Requires maintenance as falling branches/trees can take it down. Tenax plastic netting is effective but also expensive of resources and can be taken down after 3 years and re-used (expensive of labour) but much less obtrusive/visible. Vulnerable to bored youth with cigarette lighters.

Fence closure duration. Period for which fencing is maintained against deer browsing. 3 years for Tenax on hazel uprights before the hazel fails. Often 3 years for deer fencing, which may be capable for 21 years or longer, but deliberately opened to allow deer access for deer welfare reasons. But even in well-grown coppice, at high deer population density, opening to deer can have severe deleterious effects on ground flora and on saleability of a standing crop due to deer rubbing.

Deer rubbing: Damage to growing coppice stems or natural regeneration of other species by deer territory marking or de-velveting antlers in season. Reduces strength and workability of stems unless damaged sections are cut out. Cutting out takes time (reducing efficiency and profit margins) and is wasteful and may make the difference between a stem being usable for better-than-faggot use and not usable.

Derelict coppice: Hazel 25 to 75 or more years since last cut with adequate stool numbers and spacing. OR younger regrowth with deer damage making it a ‘loss’ to cut for any usable product. Capable of restoration in 3 cuts (21 years) or less given limited layering or planting of hazel combined with management of canopy trees and fencing or other management to exclude deer browsing and rubbing of stems.

Overstood coppice: Hazel out of rotation by virtue of age (8-25 or so years).

Lapsed coppice: Hazel coppice, not cut for many decades with poor stool density, spacing and stem count. Often has many canopy trees (non-hazel) often of large size. A questionable proposition for restoration as coppice.

Coppice Rotation: Period at which hazel (or other coppice species) is cut. Hazel plain coppice is 5-7 (8) years. May be overlaid with another rotation, e.g for oak standards at 80 to 120 years or longer. Mixed hazel and ash may be 7 years for hazel with ash at 21 years, so every 21 years all stools of both spp. In a cant are cut.

Fuelwood. Firewood/logs (sometimes chunks or chips). Trees cut to burn for heating or cooking, sometimes to make charcoal. Premium firewood is usually split from larger diameter straight lengths, often machine extracted and tends not to be sourced from hazel coppice or its restoration despite being of excellent fuel value when prepared for burning. Derelict hazel is difficult to cut commercially as straight lengths tend to be shorter than 2.4 or 3m needed for machine forwarding. This leads to much waste. Felling efficiently and snedding as cordwood tends to be slow compared with plantation thinnings and requires a high degree of skill. Machine forwarding tends to cause high levels of stool damage. Branchwood and canopy wood from standards tends to be wild, short and difficult to process unless cut into logs on site and then forwarded in bulk as logs.

Habitat piles. Piles of cut material stacked at intervals as habitat for fungi, small mammals and other biota. Some is good, more isn’t better. Often apparently used as a rationale for not putting in the effort to finishing a coppice cant/extracting cut material. May seriously suppress stool regrowth and/or ground flora but in instances of high deer browsing, may fortuitously protect some stools if not too dense. In urban fringe situations may result in locals holding impromptu barbecues. See Dead Hedges.

Hanger: wood on a ridgetop, often on chalk where the ridge-top soil may be clay or clay with flints and the lower slopes more-easily-ploughed chalk soil. OR a detached or partly detatched large branch suspended in a tree canopy.

Knopper gall: A parasitic gall of oaks (one of many) caused by a wasp (Andricus quercuscialis) which requires both UK native oaks and Turkey oaks for its life cycle because its generations alternate between native oaks and Q. cerris. This gall wasp became established in the British Isles in the 1970s and is now widely established. It is thought to have been imported via holidaying children collecting the startlingly-warped affected galls and bringing them home in their luggage as curiosities (as children do). Mothers (as mothers will) then threw them out and the wasp larvae or pupae later emerged.

Layers: Stems left for layering to increase stool count/density. Can work but deer browsing can kill layered stems.

Mast years: Years in which oaks produce many viable acorns (mast) which (if a mast year coincides with a coppice cut) may give rise to copious supply of seedlings in a cant and an opportunity to recruit candidates for a future generation of standards via saplings and waiver stages. Said to be every 7 years. May have been b0ll0xed by the importation of knopper gall if there are any non-UK native Turkey oaks (Quercus cerris) anywhere near.

Michaelmas growth: Abrupt, straight young growth occurring in later summer and often seen in healthy oaks. Michaelmas festival, 29^th September.

Neolithicing (Neolithicking): Going through an area of overstood or derelict coppice and cutting out the usable shoots or sunshoots and leaving all the rest. As sunshoots can be a response to shading, this can have deleterious effects on stool vigour in the medium to long term if done habitually. Also known as ‘robbing the coppice’.

Plain coppice: coppice with no standards. Efficient, can be extremely productive. Uncommon. Coppice with standards is the current ‘default standard’ for coppice managed with biodiversity as a major objective (which may be mistaken).

Retrenchment Growth:  Growth made in the canopy or canopy core of a maiden tree (possible in a cut tree) after a period of stress. Tree may be Stag headed (canopy) with the retrenchment growth pushing up between the dead branch ends from nearer the bend of the trunk. May take the form of young, straight, upright branches growing amongst more ‘wild’ canopy branches where the spreading lower canopy has died off, for instance through shading by the sub-canopy of derelict hazel. Regrowth after severe storm damage is regrowth not retrenchment growth.

Short-cut coppice. Hazel, when planted with the intention of creating new coppice can be cut at 3 years after planting to encourage stool expansion. BUT needs full light for this to be truly successful. Will not work on new trees planted amongst established trees if the established stools are not cut. BUT planting hazels amongst established regenerating hazel, especially with heavy shade often results in low ‘take’ rate of the new trees due to shading.

Sold standing: An area of coppice for which a coppice worker pays a fee to the owner before cutting the standing crop on that area, working up any/all product, selling that product and leaving the site clear with stools cut properly on completion. Standing crop: Hazel cant of agreed size/boundaries cut at no cost to landowner by a coppice worker, as ‘sold standing’. Does not include cutting the good stuff and leaving the rubbish.

Standing deadwood: Large, dead trees retained for nature conservation reasons. Standing deadwood is more valuable than lying deadwood as it often has a wider range of environmental conditions (temperature, humidity) and hence more available niches available for exploitation by biota. Note short, squat oaks may persist safely for many years owing to the durability of the heartwood. Branches tend to drop as small pieces. Regular safety assessment is required to maintain landowner’s duty of care responsibilities even away from paths – oaks will eventually fall due to rot of the roots or trunk base. Also note that standing dead oaks can furnish excellent quality already-seasoned timber. Other species offer greater safety risks and last less long. Recently-dead ash due to ash dieback can be extremely frail. Dead oaks can be excluded from counts of standards as they cast very little shade. See Stag heading (crown).

Stool Expansion: Cut a hazel stool and it re-shoots, mainly from the edges of the cut stem surfaces. The shoots compete with each other for light, with individuals on the stool edges doing better than many of those in the stool centre. When cut low, over repeated cuts hazel stools expand, tending eventually to form a ring.  Parts of the ring may die and stools may then appear as discrete individuals despite deriving from the same individual antecessor. Note that cutting high inhibits the ability of stools to expand. Also note that expansion and fragmentation of coppice would have been the main method of hazel coppice increasing in stool number and stool density over generations of repeated cutting. ‘Cut coppice to get coppice’. Hazel responds particularly well to cutting and where cutting is repeated on a site, hazel gains a competitive advantage over other species cut at the same time.

Stool contraction: The process by which hazel stools in un-worked coppice (or shaded coppice) diminish in stem count and diameter. Fragmentation may occur with parts of a very old stool dying and rotting away with other groups of stems and the supporting parts of the stool persisting.

Sub-canopy: Trees such as oak, sweet chestnut, beech, sycamore, ash left uncoppiced form a high canopy with their leaves and branches. Species such as hazel and hawthorn grow less tall and form a subcanopy under the aforementioned ‘canopy’ species.  In hazel ‘plain coppice’ hazel will form a canopy over the woodland floor with its field layer (herbaceous flora) and any shrub layer small woody species like native privet, spindle. A canopy of hazel remains a sub-canopy.

Timber: Large diameter/long lengths of wood, usually sawn.

‘Trash tree’ old but derogatory term for a tree growing amongst a coppice crop which is of no or very low value (willow, aspen) and often a nuisance to cut. Hawthorn, holly, blackthorn. May formerly have been removed (e.g. by siting a bonfire on its stump).

Underwood: Wood, usually coppice, worked as round or cleft wood of small diameter.

This video https://youtu.be/lDrq4AE5U7s explains standards and aspects of their management (and why they should be managed) in the context of hazel coppice with oak standards.

’12 per acre’. Often-quoted ‘traditional’ guide to how many oak standards there should be per acre. Includes waivers and trees may be clumped in part of a wood to encourage better form development, so giving an ‘average’ for a part of a woodland managed as coppice (not evenly spread in each cant).  Can include edge trees only partly shading a cant. Total count of waivers plus standards should equal should equal 12 but there may be only one large standard, 2 small diameter ones and the rest waivers per acre. See Canopy Trees, Conservation trees. ’12 per acre’ includes these.

15% Maximum % area of a cant that can be covered by canopy and still produce commercially viable coppice.