Scrub is Special – Save our Scrub

Scrub habitat in Betty’s Wood – home to whitethroat and yellowhammer

Scrub, as a habitat, is nearly always followed by the words “clearance” or “eradication”. How often do we read the words “it’s only scrub,” as if this is some kind of second-rate habitat to which we must do something.

A brief Google search reveals countless pages relating to wildlife groups, country parks and nature reserves, all talking about “scrub clearance”. Not to mention countless contractors offering their services, machinery, manpower and chemicals to clear scrub.

Scrub has a bad name. It has become something to be controlled, eliminated, pushed to the corners of our fields and woodlands. It doesn’t seem to be wanted, valued or loved.

Scrub is usually regenerating woodland, although in certain special situations, it may be the final, or climax, plant community. Woodland may be regenerating on a woodland site that has lost its trees, through felling, coppicing, or natural disaster, or on a previously open habitat which, for some reason or another, has ceased to be managed and is reverting to woodland. In pre-history, areas of woodland were cleared by humans, used for a while, then the people moved on, leaving the woodland to recover and regenerate via a scrub stage. Before humans made their mark, woodlands were cleared and reverted to scrub after grazing by large mammals, such as elephants. Wildwood has areas that become denuded of trees, and which regenerate. Scrub is always present, although not always in the same area, but there are always patches of scrub into which wildlife that prefers this habitat can move.

Regenerating scrub in Betty’s Wood

Scrub will also form rapidly on almost any land that is left for any length of time: heathland, fen, coastal dunes, uplands, bogs, agricultural land and even on urban or rural habitation or industrial sites that have become abandoned.

The problem we have now is that people are not itinerant – they lived in fixed communities. Almost all land has an owner, and a defined use. Woodland is not free to regenerate where it will because land is almost always designated for a purpose – be it generation of timber in woodlands, or preservation as high forest as a nature reserve, or be it arable farmland, pasture, heathland, moorland, bog, fen, coastal dunes and other habitats deemed also to be of great value. There is precious little room for scrub to squeeze into, and people don’t want it. Because other habitats have become vanishingly rare, encroachment of scrub onto these habitats becomes something that threatens them. In towns and cities, we don’t want scrubby parkland, with ever-changing areas of wood, clearings and scrub – we want nice tidy places for people to walk, sit and play – manicured habitats, effectively over-sized gardens. Scrub is perceived as providing cover for anti-social behaviour. So it must be cleared. It doesn’t look pretty.

Even in woodland, there is little room for scrub. Coppicing produces a scrub-like regrowth from the cut stems, or stools, albeit with a more uniform height and species structure. Most of our woodland species are not species of the deep forest, they are species of the forest edge, and of scrub and coppice.   Our wildlife is adapted to the cycle of clearance and regrowth. But this is a cycle that we have broken. Coppice management has disappeared from many woodlands, leaving over-stood coppice and high forest – the familiar woodland that many of us visit and many think is the only way a woodland can or should be. We manage timber-producing woodland by clear-felling and re-planting in dense, ordered stands that produce a uniform structure. Scrub has barely a chance to grow before being overtaken by the faster-growing, more useful and more profitable softwood conifers. It is relegated to small strips around the edge and along woodland rides, if it is allowed to grow at all. Coppicing does survive, as does continuous cover forestry with natural regeneration, both of which help. But many woodlands are simply unmanaged.

Scrub in Betty’s Wood

If this were wildwood, it wouldn’t be such a problem. Areas would naturally fall in high winds, succumb to fire or grazing, or be felled by itinerant humans or large animals. But it isn’t wildwood, and hasn’t been since humans appeared on the planet. Even worse, most areas of woodland are such small remnants of our forest cover that they are simply too small to support a mosaic of habitats, including scrub, as they stand. They are left to become high forest, with no mechanism to support regeneration, no mechanism to support a cycle of regrowth.

In addition, scrub is not allowed to develop anywhere else. Pieces of woodland are simply not allowed to “contaminate” farmland, river edges, heathland, moorland, fenland or urban and suburban parks and gardens. They are cleared up – sometimes with good justification but very often without. Agricultural stewardship schemes usually require the removal of scrub. Woodland schemes also fail to recognize the importance of scrub, or allow for its management.

So does this actually matter? Well, yes it does, because many important, declining species are actually species that prefer scrubland, and enjoy the variety of species, height of vegetation and density of vegetation that scrub can provide. These include plants themselves, lichens, bryophytes, insects, mammals, birds, amphibians and reptiles. The pearl-bordered fritillary butterfly, the adder and common toad, mammals such as dormice, and birds such as blackcap, bullfinch, linnet, reed bunting, song thrust, willow tit, yellowhammer, dunnock, goldcrest, nightingale, tree sparrow and turtle dove. Many of these are disappearing as we over-clear scrub habitats and under-manage woodland.

Regenerating Birch Scrub on site of old building

The problem is that scrub does need some kind of management, whether you want to keep it or not. This can include resumption of coppicing within woodlands or at the woodland edge to create scrub, cyclical cutting of scrub to ensure a steady supply for scrub species, selective conservation grazing of low intensity by relatively hardy livestock, or by leaving small areas of scrub to develop around the edges of other habitats. Keeping scrub as scrub, and developing a good mosaic requires management, or it will revert to woodland or coppice – so attention needs to be paid to ensure that a wide variety of species, density and height are achieved. This is not easy to do, and there is a lot of debate about how to do this, or whether to do it.

In our own woods, we have some good areas of regenerating scrub at the edge of Betty’s Wood. And into this scrub we have attracted willow tit, whitethroat, yellowhammer, bullfinch, linnet, song thrush, goldcrest, dunnock, woodcock and others. Coppicing will, in time, produce a rotation of scrubby habitats for species to move into, as well as allowing the next generation of mature trees to emerge, and producing a sustainable crop of wood for crafts and firewood.

Our Coppice – varying ages and densities

Coppice from 2 (foreground) and 4 (background) years ago showing regrowth

The problem is that management of scrub has been seen as synonymous with clearance or eradication, despite it being quite clear in the Scrub Management Handbook, and the JNCC Report, that this is only ONE option, and even then, where possible a patchwork of scrub areas should usually be allowed to remain. Maybe this is because the focus has been on removal of scrub, so there has been more research into, and thus the handbook provides more information on this aspect of management. Certainly the other options given in these documents – create, enhance, preserve – seem to have been forgotten.

In addition, on woodland nature reserves and other public wooded spaces, the public perception is that these should be left alone, and that high forest is best. There is undoubtedly an argument for leaving some areas wild, and ancient woodland and veteran trees undoubtedly support a very biodiverse ecosystem, but leaving everything alone will result in a closed canopy woodland with lower diversity than a managed woodland that includes ancient and veteran trees.

Oak glade in spring – ancient and diverse high forest habitat

People don’t like to see trees being cut down, so managers of public land don’t cut them down – it is the easiest option. It would be lovely if areas of woodland were extensive enough to allow natural processes of regeneration to take place – but few sites are large enough. The average size of a piece of woodland in England is about 8ha. So the management methods that create scrub are not being carried out, nor is scrub being created naturally. At the same time, people are receptive to the idea of clearing scrub – the combined effect is that scrub is reduced in extent and diversity, and often confined to margins of roads and railways, and to derelict urban sites awaiting development.

High Forest – the popular perception of what woodland should be like

We hardly ever see the word “scrub” in management plans for nature reserves unless it is followed by the word “clearance”. There are clearly habitats where scrub needs to be cut, or it will overwhelm other valuable and vanishing habitats, but it is really important to ensure that an area of scrub is left, and managed on rotation, so there is always somewhere for scrub species to go. There is a need to question whether complete scrub removal is required. Areas of scrub also need to be left in urban and suburban green spaces. They are amazing places for children to explore, and learn, as well as being repositories of wildlife. They may not look tidy, but neither do uncut road verges – yet many councils are taking up Plantlife’s campaign to leave some area of verge to grow wildflowers, so why not take up the cause of scrub, and leave some areas of urban parks to develop as scrub habitat?

There seems to be a real need to educate people as to the value of scrub, and the related woodland coppice habitat, so that they can understand the need to keep some scrub, and to create coppice. To do this, the mindset that cutting down trees is “bad” and clearing scrub is “good” needs to be changed. In addition, there needs to be support for scrub habitat – not just the specialised communities in rare scrub habitats, but good old-fashioned lowland scrub – within stewardship schemes, woodland grant schemes and within urban and suburban green spaces.

Not all scrub is bad. A lot of species depend on scrub, and on an ever-changing and evolving patchwork of vegetation from open meadow to high forest, and everything in between. The in between bits are important. Scrub is important. Save our Scrub!

Willow tit – a red-listed species that depends on scrub habitat

Resources:

JNCC Report 308: Mortimer, S.R., Turner, A.J., Brown, V.K., Fuller, R.J., Good, J.E.G., Bell, S.A. Stevens, P.A., Norris, D., Bayfield, N. and Ward, L.K. – (2000) – The Nature Conservation Value of Scrub in Britain – Available from http://jncc.defra.gov.uk/page-2445

FACT in conjunction with English Nature (2003) The Scrub Management Handbook – ISBN 1 85716 745 7 – Available from http://publications.naturalengland.org.uk/publication/72031

Fuller RJ and Warren MS (1995) – Management for Biodiversity in British Woodlands – Striking a Balance – from British Wildlife (1995): 7; 26-37 – Available from http://www.britishwildlife.com/classicarticlesview.asp

Fuller RJ and Warren MS – Coppiced Woodlands: Their Management for Wildlife (1993) – available from http://jncc.defra.gov.uk/page-2640

Gough SJ and Fuller RJ (1998) – Scrub Management for Conservation in Lowland England: Practices, Problems and Possibilities

BTO Research Report No. 194 ISBN 0 903793 96 2 – available from http://www.bto.org/sites/default/files/u196/downloads/rr194.pdf

See Also

A great album of photos of scrub regenerating on Exmoor – by Hen

 

Coppicing

This year’s coppice showing the cut stems and large amount of light coming into the area

Coppicing is a traditional form of woodland management.  It seems counter-intuitive to cut down trees when you are trying to preserve ancient woodland but this is exactly what is needed.

First of all, a lot of species do not live very long unless they are coppiced.  By coppicing I mean cutting the tree down to allow it to sprout again from the base.  Hazel, in particular, thrives upon coppicing, living many times longer if it is repeatedly cut and allowed to regrow than if it is just allowed to grow and decay.  Other coppice species include ash, sweet chestnut, sycamore (not in our ancient woodland!), oak, willow, birch and alder.  Shrubs such as hawthorn, crab apple, holly and elder also coppice well.  In fact most trees will coppice provided they are not too old when cut, and provided the stems are protected from browsing while they are regrowing.

Our great ancient oak trees are not suitable for coppicing, but a relatively large area of our woodland has young, scrubby trees growing fast and crowding out each other and the light.  It also has an un-managed hedge boundary between the main woods and Betty’s Wood that can be revived by coppicing.

We started coppicing in 2009-10, cutting an area of predominantly willow, hawthorn, oak and a bit of hazel.  Since then we have extended the coppice area.

The photos here show a sequence:  the top photo is what an area is like when it has first been cut.  It looks bleak and empty, but it is not.  The key thing is that we have let in a lot of light to the area and this will stimulate both regrowth and regeneration.  At this stage we can do some targeted planting if we want to improve the diversity of the area.

Coppice from 2 (foreground) and 4 (background) years ago showing regrowth

The next photo shows coppice that was cut 2 years ago.  It is regrowing quite strongly.  You can see we have protected the stumps (called coppice stools) using a combination of stock netting and chicken wire to prevent browsing of the new shoots by deer and rabbits.  This is essential – browsing can easily kill a regenerating coppice stool.  You can also see that there is a lot more ground flora in this area. A lot of woodland plants rely on coppicing to thrive, coming up periodically in the cleared areas to benefit from the light.  As well as some bramble, we have a patch of violet in this area, and the bluebells are spreading into what was once a sterile piece of ground.  Finally, we get natural regeneration happening – willow and birch seedlings are thriving because they have access to light, and where they come up, we provide them with protection.

Coppice cut 4 years ago showing strong re-growth

Above we have a piece of coppice that was cut four years ago.  The regrowth on the willow, in particular, is over 10 feet/3metres, and the poles are 3 to 5 cm diameter at the base.  The hawthorn and oak are regrowing more slowly and will be cut less frequently.  There are some young oak that we are leaving to grow up as specimen trees or “standards” in our “coppice-with-standards” system.  We have also done some planting to increase the amount of hazel and ash in this area.  The regrowth will result in us being able to cut it again at about 7 to 10 years, and thus have a sustainable source of wood for craft, habitat and firewood.

We do the work ourselves.  It is not always straightforward as you can see below with a sequence of photos from the past weekend.

A difficult twin-stemmed holly needs winching down

This year we are, amongst other things, clearing a patch of holly.  This has been slowly invading the coppice area and the problem is that it cuts out the light, particularly in the spring, which holds back regeneration.  Holly springs back very quickly, usually from root suckers, so we are not destroying this patch of holly, just reviving it, and allowing the coppice to thrive too.  However coppice species often have multiple and quite inter-twined stems.  This particular holly was separated at the base, and had welded itself together higher up, which mean both stems had to be felled together.  The area was confined, and the holly got “hung-up” rather than falling straight down.  we had to set up a winch to roll the tree away from the branches that were holding it.

Setting up the winch

We were using another, larger tree as a winch point, and you can see in the foreground the log pile, a brash pile (leaves and smaller stems) and behind that a habitat pile.  About 1/3 to 1/2 the brash will be left as habitat piles for birds and mammals to nest in, and the rest will be chipped to provide a good, dry surface on our paths and they will eventually rot down.  The log pile will be used mainly for firewood but the straighter stems may be used for rustic furniture making and some green wood turning.  We select wood that has crevices and particularly wood that is already a little bit rotten for the habitat pile.  Very large logs usually come from fallen branches, and we use these as sitting logs around the woods, and they provide habitat as they gradually decay.

Felled holly tree

We finally managed to fell the large holly (about 40ft, 13 metres tall), and here it is on the ground.  The smaller stem is underneath slightly to the right and cannot be seen in this photo.

Felled holly showing just how much light is now coming in.

And here are the final results.  You can see just how much more light is being let in.  The ring of stumps around the large oak are all holly, and you can see just how much it was dominating the area.  We still have to cut the hazel in the hedge in the background, and then our coppice will be open to the sun and ready to regrow strongly.  There is a lovely standing dead tree in the background too, providing excellent habitat for wildlife.  We leave our standing deadwood as habitat, and have no plans to fell this old tree.

In future we will extend our coppice along Betty’s Wood boundary to refresh the boundary hedge.  We always leave joined-up canopies as a route for dormice (although we have no evidence that they are present despite a survey for them), and never fell old trees with holes and hollows that are good habitat for owls, bats and other creatures.  The younger trees, however, should respond very well and the whole woods should be rejuvenated.  The coppice only comprises about 1/5 of the woodland.  There are other areas and plenty of other habitats being managed in different ways.  We have some areas planted with young trees that will become coppice of the future in the ancient woodland and in Betty’s Wood which was planted in 2010-11.

Coppicing is part of the way in which we try to ensure that there is an excellent variety of habitats in our woods – we also have mature ancient trees, wood pasture, wildflower meadows, hedgerows, dead hedges, thickets, areas that will become continuous cover forestry, and wet woodland, as well as eleven ponds.  The wildlife has already responded and we hope to report more and more species making their homes in our woods in the future.