Native trees
Alders
Alder (Alnus glutinosa)
Apples
Crab Apple (Malus sylvestris)
Ashes
Common Ash (Fraxinus excelsior)
Birches
Silver Birch (Betula pendula)
Downy Birch (Betula pubescens)
Box
Box (Buxus sempervirens; southern England only)
Cherries and Plums
Wild Cherry (Prunus avium)
Bird Cherry (Prunus padus)
Blackthorn (Prunus spinosa)
Elms
Wych Elm (Ulmus glabra)
English Elm (Ulmus procera; southern Great Britain only; doubtfully native)
Smooth-leaved Elm (Ulmus minor, syn. U. carpinifolia; southern Great Britain only)
Hawthorns
Common Hawthorn (Crataegus monogyna)
Midland Hawthorn (Crataegus laevigata; southern Great Britain only)
Hazels
Common Hazel (Corylus avellana)
Hornbeams
European Hornbeam (Carpinus betulus; southern Great Britain only)
Hollies
European Holly (Ilex aquifolium)
Junipers
Common Juniper (Juniperus communis)
Lindens (Limes)
Small-leaved Linden/Lime (Tilia cordata; southern Great Britain only)
Large-leaved Linden/Lime (Tilia platyphyllos; southern Great Britain only)
Maples
Field Maple (Acer campestre; southern Great Britain only)
Oaks
Pedunculate Oak (Quercus robur)
Sessile Oak (Quercus petraea)
Pines
Scots Pine (Pinus sylvestris)
Poplars
Aspen (Populus tremula)
Black Poplar (Populus nigra; southern Great Britain only)
Rowans and Whitebeams
European Rowan (Sorbus aucuparia)
Common Whitebeam (Sorbus aria) and several related apomictic microspecies
Service Tree (Sorbus domestica; recently discovered growing wild on a cliff in south Wales)
Wild Service Tree (Sorbus torminalis)
Willows (Salix spp.; several species)
Bay Willow (Salix pentandra)
Crack Willow (Salix fragilis)
White Willow (Salix alba)
Almond-leaved Willow (Salix triandra)
Yews
European Yew (Taxus baccata)
Native large shrubs
These larger shrubs occasionally reach tree size:
Alder Buckthorn (Rhamnus frangula)
Purging Buckthorn (Rhamnus cathartica)
Elder (Sambucus nigra)
Common Dogwood (Cornus sanguinea)
(Common) Sea-buckthorn (Hippophae rhamnoides)
Spindle (Euonymus europaeus)
Sallow, Goat Willow (Salix caprea)
Grey Willow (Salix cinerea)
Naturalised trees
From Europe
European Pear (Pyrus communis; sometimes regarded as native)
Plymouth Pear (Pyrus cordata; sometimes regarded as native[1])
Cherry Plum (Prunus cerasifera)
European Beech (Fagus sylvatica; widely considered native to southern England, but probably a stone-age human introduction[2])
Sycamore (Acer pseudoplatanus)
Norway Maple (Acer platanoides)
Sweet Chestnut (Castanea sativa; a Roman introduction)
Pollarding is a pruning system in which the upper branches of a tree are removed, promoting a dense head of foliage and branches. It has been common in Great Britain and Europe since medieval times and is practiced today in urban areas worldwide, primarily to maintain trees at a predetermined height.
Traditionally trees were pollarded for one of two reasons: for fodder to feed livestock, or for wood. Fodder pollards produced "pollard hay", which was used as livestock feed; they were pruned at intervals of 2-6 years so that their leafy material would be most abundant. Wood pollards were pruned at longer intervals of 8-15 years, a pruning cycle that tended to produces upright poles favored for fence rails and posts as well as boat construction. One consequence of pollarding is that pollarded trees tend to live longer than unpollarded specimens because they are maintained in a partially juvenile state, and they do not have the weight and windage of the top part of the tree.
As in coppicing, the tradition of pollarding is to encourage the tree to produce new growth on a regular basis in order to maintain a supply of new wood for various purposes, particularly for fuel. In some areas dried leafy branches are stored as winter fodder for stock. Depending upon the use of the cut material, the length of time between cutting will vary from one year for tree hay or withies, to five years or more for larger timber. Sometimes only some of the regrown stems may be cut in a season – this is thought to reduce the chances of death of the tree when re-cutting long-neglected pollards.
Pollarding was preferred over coppicing in wood-pastures and other grazed areas, because animals would browse the regrowth from coppice stools. Historically, the right to pollard or "lop" was often granted to local people for fuel on common land or in royal forests; this was part of the right of Estover.
An incidental effect of pollarding in woodland is the encouragement of underbrush growth due to increased levels of light reaching the woodland floor. This can increase species diversity. However, in woodland where pollarding was once common but has now ceased, the opposite effect occurs as the side and top shoots develop into trunk-sized branches. An example of this occurs in Epping Forest in London/Essex, UK, the majority of which was pollarded until the late 19th century. Here, light levels on the woodland floor are extremely low owing to the thick growth of the pollarded trees.
Pollards cut at only about a metre or so above the ground are called stubs (or stubbs). These were often used as markers in coppice or other woodland. Stubs cannot be used where the trees are browsed by animals, as the regrowing shoots are below the browse line.
As with coppicing, only species with vigorous epicormic growth may be made into pollards. In these species (which include many broadleaved trees but few conifers) removal of the main apical stems releases the growth of many dormant buds under the bark on the lower part of the tree. Trees without this growth will, of course, die without their leaves and branches. Some smaller tree species do not readily form pollards, because cutting the main stem stimulates growth from the base, effectively forming a coppice stool instead. Examples of trees that do well as pollards include broadleaves such as beeches (Fagus), oaks (Quercus), maples (Acer), black locust or false acacia (Robinia pseudoacacia), hornbeams (Carpinus), lindens or limes (Tilia), planes (Platanus), horse chestnuts (Aesculus), mulberries (Morus), Redbud (Cercis canadensis), Tree of Heaven (Ailanthus altissima) and willows (Salix); also a few conifers, such as yews (Taxus).
Pollarding is also used in urban forestry in certain areas for reasons such as tree size management, safety and health concerns. It removes rotting or diseased branches for the overall health of the tree, living and dead branches that could harm property and people, as well as expanded foliage in spring for aesthetic, shade and pollution concerns. Trees may be "rejuvenated" by pollarding – for example Bradford pear (Pyrus calleryana "Bradford"), a beautiful flowering species when young, but brittle and top-heavy when older.
Oaks, when very old, can form new trunks from the growth of pollard branches - i.e. surviving branches which have split away from the main branch naturally.
http://en.wikipedia.org/wiki/Pollarding
Coppicing is a traditional method of woodland management which takes advantage of the fact that many trees make new growth from the stump or roots if cut down. In a coppiced wood young tree stems are repeatedly cut down to near ground level. In subsequent growth years, many new shoots will emerge, and, after a number of years the coppiced tree, or stool, is ready to be harvested, and the cycle begins again. (Note that the noun coppice means a growth of small trees or a forest coming from shoots or suckers.)
Typically a coppiced woodland is harvested in sections or coups on a rotation. In this way, a crop is available each year somewhere in the woodland. Coppicing has the effect of providing a rich variety of habitats, as the woodland always has a range of different-aged coppice growing in it, which is beneficial for biodiversity. The cycle length depends upon the species cut, the local custom, and the use to which the product is put. Birch can be coppiced for faggots (bundles of brushwood) on a three or four year cycle, whereas oak can be coppiced over a fifty-year cycle for poles or firewood.
Coppicing maintains trees at a juvenile stage, and a regularly coppiced tree will never die of old age—some coppice stools may therefore reach immense ages. The age of a stool may be estimated from its diameter, and some are so large—perhaps as much as 9 metres (30 ft) across—that they are thought to have been continuously coppiced for centuries.
Coppiced stems are characteristically curved at the base. This curve occurs as the competing stems grow out from the stool in the early stages of the cycle, then up towards the sky as the canopy closes. The curve may allow the identification of coppice timber in archaeological sites—timber in the Sweet Track in Somerset (built in the winter of 3807 and 3806 BC) has been identified as coppiced lime.[3]
In the days of charcoal iron production in England, most woods in ironmaking regions were managed as coppices, usually being cut on a cycle of about 16 years. In this way, fuel could be provided for that industry, in principle, forever.
In southern Britain, coppice was traditionally hazel, hornbeam, beech, ash or oak, grown amongst oak or sometimes ash or beech standards. In wet areas alder and willows were used. These coppices provided wood for many purposes, especially charcoal which before coal was economically significant in metal smelting.
The variation of coppicing known as coppice with standards (scattered individual stems allowed to grow on through several coppice cycles) has been commonly used throughout the British Isles as a means of giving greater flexibility in the resulting forest product from any one area. Not only does the woodland provide the small material from the coppice but also a range of larger timber for jobs like house building, bridge repair, cart making and so on.
The shoots (or suckers) may be used either in their young state for interweaving in wattle fencing (as is the practice with coppiced willows and hazel) or the new shoots may be allowed to grow into large poles, as was often the custom with trees such as oaks or ashes. This creates long, straight poles which do not have the bends and forks of naturally grown trees. Coppicing may be practiced to encourage specific growth patterns, as with cinnamon trees which are grown for their bark.
Coppiced hardwoods were extensively used in carriage and shipbuilding, and they are still sometimes grown for making wooden buildings and furniture.
http://en.wikipedia.org/wiki/Coppicing
