Woodland edges, both on the outside of the wood, and along tracks and glades within the woodland area, are very valuable habitats. They provide a range of conditions of light and shade, shelter and exposure, and can support a wide variety of plants from mosses and lichens, herbs and grasses through to shrubs and trees. The management of the edge is very important in providing sheltered conditions for the woodland within. The woodland edges are also the parts which are most valued by people for recreation, although woodland edges which are ‘overgrown’ may also invoke feelings of fear. Rides, glades and clearings not only provide open, sheltered, sunny spaces within the wood, but add to the amount of woodland edge.
Most woodlands have a proportion of open space, and plantations and other woods require roads and tracks for management. The Woodland Grant Scheme normally permits 20% open space of the total area receiving grant, with trees planted at 2250 per hectare (2m spacing) or 1100 per hectare (3m spacing). For woods not receiving grant aid, up to 30% open space may be appropriate. More than about 50% open space creates a park or pasture wood landscape, with clumps or bands of trees with linked open spaces. The nature of open space will change as the trees grow (see diagrams below).
Access
First mark any existing access routes across the site, either official rights of way or other unofficial paths. These paths are likely already to follow the shortest and easiest route, and there is no point in making them longer or more difficult. The use of ‘desire lines’ is strong, and young trees will not survive the trampling of existing patterns of use. In large areas of planting, it’s possible to leave sufficient space between the trees that the path or ride remains open to the sunlight. This needs a strip at least 12m wide. In smaller areas of planting there is not space for such wide rides at the same time as creating a mainly woodland habitat, and paths will need to go under the canopy.
Minor paths which are to go under the canopy can be planned at this stage, or can be left to be created by use or clearance as the woodland develops. Generally it’s easier to plan paths at the beginning of the project, when the best routes can be picked out on the ground, and before they are obscured by growth.
Avoid creating wind-tunnels, which will lessen the value of tracks and rides for wildlife or recreation. Rides can be angled just before emerging from the woodland, especially at edges which face the prevailing wind. Occasional distinct curves along rides will lessen the wind tunnel effect, and bays and scallops along the woodland edge (see below) will help provide sheltered conditions.
The width, orientation and height of the surrounding trees affects the conditions of sun and shade. East/west orientations give more sun during the summer, whereas a north/south orientation gives more sun in the winter. generally, open rides need to be 1.5 times as wide as the height of the surrounding trees. A ride running through mature woodland of lime, ash, beech, oak or hornbeam, which may reach 20-30m height, will need to be at least 30-45m wide to benefit those species, and especially butterflies, which need the most sunlight. This width of ride is only possible in large woodlands of 10 hectares or more.
In a coppiced wood, where the maximum tree height is reduced by frequent cutting, rides can be narrower and remain sunny. A hazel coppice, for example, might reach a height of about 6m before it is cut, so rides of about 9m width will remain open to the sun. Typical species of a spinney are the small, spiny species of hawthorn and blackthorn, through which it is also easier to retain sunny open space. Copses and spinneys are good ways of providing woody cover on small patches of land, but will not develop the diversity of a woodland.
Open spaces
If the area is greater than about one hectare, it will be feasible to make one or more open glades within the woodland. These should normally be linked with paths to ease management. a glade needs to be at least 500 square metres in order to retain its open character as the trees around it grow up. In mature woodland, where trees are 20-30m tall, an open space needs to be at least 2,500 square metres, or a quarter of a hectare, to retain its open, sunny character.
Ground treatment
If starting with bare ground, rides and other spaces can be sown with suitable mixtures of native seeds, or can be left to regenerate naturally. Where rides and open spaces are already grassy, the easiest option is to retain the grass cover, and mow it as necessary. Collect up the mowings and pile them up nearby to be used later as mulch around the trees. Collection will help impoverish the grass, so that other species are able to move in. Removal of turf to create patches of bare ground may be an option. Gravel surfacing laid down for tracks or paths is not necessarily a minus for biodiversity, but may develop a more varied flora than was there previously.
Edges
Within the boundaries of the planting site, define the edges. These should be varied to fit the landform, drainage patterns, and to take account of views into and out of the site. Where the site abuts onto private gardens it is essential to consult residents, who will not want their gardens or houses shaded or their views obscured. In an area surrounded by housing, a central clump of planting, with smaller clumps grading to the edges of the site may be more acceptable than a solid block of woodland. An area of mown grass around the woodland will enhance its appearance, and increase accessibility into the woodland.
Management of edges
The management of edges, both those on the outside and those within the wooded area, needs to be planned at an early stage, as it will affect the choice of species and spacing. The planning of edge planting is also very important for shelter, with those on the outer, windward edge of the wood being most important. The most valuable edges for insects and birds are the sunny south and west facing edges, so it’s best to concentrate effort on edges with these aspects.
For diversity of wildlife along the edges of glades and rides, a three-zone system is best. As shown in the diagram, the shrub layer is coppiced, and the tall herbaceous layer and the grassy verge are mown, at the varied frequencies shown. Note though that this system may not be compatible with encouraging feelings of safety.
Diversity can be increased more if alternate edges are cut in different years, as shown below.
Bays or scallops can be incorporated into the design of a road or ride to provide a natural, undulating line. If placed in opposing positions, more light across the ride will be created. The smallest bay length which is useful is 7m (23’), but if the trees have an ultimate height of more than 20m (66’), bays will need to be a minimum of 25m (83’) long to admit enough light.
At intersections of rides and tracks, larger glades which allow light in from various angles can be created by leaving the corners unplanted.
Trying to create glades or widen rides in existing woodland is not easy. This will open up the woodland, typically leaving an exposed edge of bare trunks and branches which looks unattractive, and exposes the woodland to cold winds and possible wind damage.
Ponds and streams
Ponds, streams and marshy ground are valuable habitats in themselves, and their presence in a woodland greatly increases the site’s diversity, as well as adding to its amenity value. However, heavily shaded ponds are of much less wildlife value, and it’s important that new planting does not encroach on their open, sunny margins. With streams, at least half should be open to sunlight, with the remaining portion under intermittent shade from light-canopy trees and shrubs.
Herbicides should not be used within 10m (33’) of streams, or 20m (66’) of reservoirs.
Local identity
At an early stage, name the wood and give a name to the features within it. Choose names with local associations, or which relate to the physical features of the site or the activities various areas are used for. Such names usually arise naturally amongst people who use the site, but it’s easier if there is a consensus about what is what! Obvious and sensible names refer to the species planted, for example,
‘the birches’ or ‘the alders’, or to the planting pattern or structure of the trees, for example ‘the avenue’ or ‘the coppice’. Valleys, ridges and ponds are obvious features for naming, along with use-related locations such as ‘the picnic place’, ‘the cricket pitch’. Sometimes the shape of a space or area of planting leads to a name such ‘the airstrip’ or ‘the triangle’. If the new woodland incorporates some existing trees, you may find that any old or unusual trees have local names. Trees used for climbing and play quickly acquire names among local children.
