How to Rewild

Dense Scrub

Habitat Management Plan

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Dense Scrub
Habitat Guide

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Scrub is one of the most undervalued of British habitats, perhaps because it is also the most invasive. This dense vegetation not only supports a diverse population of animals, but also creates a protective nursery for trees. As the saying goes, ‘the thorn is the mother of the oak’ – where natural regeneration of trees is held back by deer and sheep grazing, thickets are about the only places where new woodlands can form.

But Dense Scrub is valuable on its own merits, for many of the same reasons as a hedge – it creates an impenetrable refuge for small mammals and birds, while providing fruit, nuts, leaves and nectar throughout the year. Scrub is not a permanent habitat – it is ‘seral’ – a transition stage between grassland and woodland, and it will spread quickly if left unchecked.

If you’re managing land with scrub, it’s worth being aware that this habitat has negative cultural and political connotations in some areas. As scrub spreads quickly through unmanaged grassland, it may be seen in some rural communities as a sign that a landowner has abandoned their duty of care. Indeed, the Basic Payments Scheme defined a farmer in 2023 as someone who ‘keeps some land in a state suitable for grazing or cultivation by keeping it clear of any scrub that cannot be grazed (sometimes known as ‘dense scrub’).

Sub Habitats

Scrub dominated by the very spiky, sloe berry-bearing plant Blackthorn (Prunus spinosa).

Scrub dominated by the nut-bearing tree Hazel (Corylus avellana), which may be coppiced to produce rods.

Typically sand dune scrubland, dominated by the spiky, orange berry-bearing plant Sea Buckthorn (Hippophae rhamnoides). Reputed to be ‘non-native’ outside of East England, though this is disputed.

Scrub dominated by the spiky, blackberry-bearing Bramble plant (Rubus fruticosus).

Scrub dominated by the densely-spined, yellow-flowered Gorse plant (Ulex europaeus).

Scrub dominated by the spiky, red berry-bearing Hawthorn plant (Crataegus monogyna).

Scrub dominated by the invasive non-native, flowering Rhododendron (typically Rhododendron ponticum).

Scrub with no one dominant species – typically a mix of bramble, hawthorn and blackthorn species, though other plants may also form a mixed scrub complex.

Scrub dominated by one or more species of Willow (Salix spp.) – these are readily coppiced to produce biomass and withies.

Scrub dominated by the densely-spiked, blue berry-producing Juniper plant. A very uncommon habitat compared with other types of scrub.

Value

Just like artificial Hedgerows, its wild equivalent, Dense Scrub, provides a wide range of different services for wildlife:

  • refuge from predation and weather
  • nesting and roosting opportunities
  • fruit, nuts, nectar and leaves to eat
  • lookout posts
  • hunting spots
  • ambush opportunities
  • twigs and leaves for nesting material
  • protection for the formation of woodland

 

While scrub isn’t linear, like a hedgerow, it usually benefits from being wider, and often taller, than a typical hedge. Many birds, like the Nightingale and Lesser Whitethroat, prefer nesting in scrub that is much deeper than a standard hedge, due to the protection this provides them. And deeper scrub allows small stands of trees to grow within a single clump.

There are a wide variety of different scrub types, and these vary in their value for wildlife. On one extreme is non-native Rhododendron, which creates inhospitable conditions at ground level while producing toxic leaves and spreading rapidly.

Gorse and Sea Buckthorn tend to be highly-invasive natives, but the former produces abundant nectar, while the latter has fruits. Both are common in dune systems, where they can stabilise the shifting sands more than a grassland, and create high value structural diversity in these low habitats. Native Juniper spreads slowly and is a threatened habitat, but provides only a meagre fruit crop and the fairly sparse, small bushes create little shelter.

Other types of scrub have a more well-developed community of plants associated with them, creating a more biodiverse habitat. However, Blackthorn, Bramble and Mixed Scrub can all be highly invasive, which can create issues when they overwhelm sensitive grassland habitats. In contrast, Hawthorn, Hazel and Willow typically spread with seed, rather than root suckers, slowing their rate of colonisation. Hazel and Willow are both useful coppice products, without the thorns of many other scrub species.

Dune scrub
Gorse (pictured) and Sea Buckthorn are a common form of scrub on sand dunes, where they are part of the transition towards higher nutrient soils and taller vegetation.

Protect

Protecting scrub is not the same as leaving it alone. The habitat will revert to woodland if it is abandoned, and this process tends to be permanent, especially in the UK, where we lack forest fires and elephants (which repeatedly destroy trees on a large scale). Broadleaved Woodland is very hard to remove once it is established.

As the renowned ecologist Oliver Rackham stated time and again; cutting down a woodland doesn’t kill it – ‘British woodlands (except pine) burn like wet asbestos’ – trees regrow from cut stumps, seedlings pop up, root suckers emerge. Even when land is cleared of forest, it returns quickly from the seedbank, like in New England where 180 years of woodland clearance was completely undone in the 19th century due to the collapse of the local economy. So, are you sure that woodland is your goal? If not, then scrub clearance is an essential part of your management plan.

In wild mosaic habitats, the balance between grassland, scrub and woodland is kept in check by a number of factors that either aren’t present in Britain, or are hard to recreate…

Flooding can kill off both woodland and scrub, so beavers are an ally in scrub management; wildfire is a natural control, especially on gorse, but fires release carbon into the atmosphere. Grazing the land at extra-high stocking density every so often can prevent scrub from encroaching, or even reverse the spread of scrub, with the right livestock:

  • Bison break open dense scrub and light woodland, then browse it back
  • Cattle trample brambles and browse scrub edges
  • Deer browse scrub edges
  • Goats can remove scrub entirely (but kill trees)
  • Ponies browse gorse and graze grass, keeping the sward height low to prevent scrub regrowth
  • Soay and Hebridean sheep control low scrub effectively and graze grass
  • Pigs turn over the soil, and can eat some scrub roots

 

With the exception of bison, goats and perhaps some sheep, herbivores rarely cause substantial damage to scrub, except when it is in poor condition and liable to collapse, or very early in its growth and highly palatable. To remove scrub with livestock usually requires overstocking them in fenced-off areas for a limited time, to force large animals into dense stands of bramble etc, allowing them to trample it down. The siting of watering holes and troughs also increases local grazing pressure, which, in turn, resists the encroachment of scrub.

Soay and Hebridean sheep may be a useful long term ally for scrub control, as they browse brambles and other scrub. Soays are used in Cheddar Gorge and further north at the Severn Gorge for scrub control and to maintain the biodiverse grassland, keeping scrub in check. On our own rewilding project, we’ve found that primitive goats are very effective at removing brambles, though they’re less keen on eating blackthorn. They’ve driven back the encroaching edge of scrub by about a metre in a year, with free reign over the area when they visit once or twice per week.

However, goats pose a significant risk even to mature trees, as they strip bark from most native species except Hawthorn and Field Maple. They are excellent escape artists and also stand on hind legs to eat from the top of tree shelters. Nevertheless, goats are also some of the only animals which can effectively remove rampant gorse. Soay and Hebridean sheep need strong fencing (or NoFence collars) and prefer to graze on broadleaved plants rather than grasses, so overstocking them can be damaging to woodland and wildflowers.

Rhododendron ponticum is an invasive type of non-native scrub, with special measures required to prevent its spread – no livestock can control it, so human intervention is essential. More details are provided in the Rhododendron guide.

Calcareous grassland
On grassland that is no longer grazed, it takes little time for scrub to become established and spread across the habitat, like this Hawthorn Scrub on a Calcareous Grassland coastal slope.

Restore

The spread of scrub and the philosophy of rewilding can be difficult to balance on smaller plots of land. In the absence of a large, diverse and correctly-stocked guild of herbivores, keeping this habitat ‘wild’ and biodiverse usually requires a lot of manual labour with a saw, loppers and a brushcutter. This might feel counter to rewilding principles, but think of yourself as a replacement for these missing herbivores and you’ll begin to understand the importance of your role.

While woodland can indeed be very valuable, rewilders typically try to avoid it taking over the entire landscape, opting instead for a mosaic of different habitats, maximising the edges, where most biodiversity lies. This reflects what you would likely have seen in a wild British landscape, before humans arrived. Rewilding is *not* meant to be goal-oriented, but it *is* meant to replicate natural conditions – that’s the tightrope we are walking here.

Bringing scrub back to health is similar to the way that an underwood is maintained – coppicing is not too different from scrub management. Scrub can be cut on a 7-year cycle, just like Hazel, which will rejuvenate the stands, preventing the habitat from succeeding to woodland. However, it is worth leaving a few patches of scrub to revert to woodland, as this will improve the structural diversity of the landscape, creating new opportunities for wildlife. Old stands of scrub also have a rich supply of deadwood, which is a valuable habitat.

Scrub can be cut back using loppers, chainsaws, and a brushcutter with a metal blade during winter. The bushes and climbers, once cut down to ground level, will resprout rapidly with multi-stemmed shoots. It is good practice to leave chopped stems and a few mature shrubs within the cut area as a refuge. You can create some standing deadwood by ‘ring-barking’ a mature shrub at the base (cut all around, then peel off a few inches of bark). Regular burning is to be discouraged as this kills organisms which have survived scrub control, although occasional wildfire may be beneficial to biodiversity.

If you’re missing scrub and want to create patches of it, or improve the diversity, then it’s best to look at your existing hedgerows. These are the perfect source for seeds, with higher genetic diversity than a plant nursery – gather the fruit and seeds in autumn and scatter them in selected places across your land – ‘scrub islands’. Cover these islands with brash – cuttings from the hedgerow – to avoid mowing, grazing or walking over them.

If you’re missing hedgerows, you can do the same thing in autumn and winter by collecting seeds and cuttings from local hedges on road verges (be careful of traffic!). Rather than brash, use bamboo canes to mark out the edge of your scrub islands. It’s legal to take cuttings and seed from most plants on public land in the UK – though there are exceptions in nature reserves, SSSIs and for some rare species. Speaking from experience, this method of harvesting plant material might be legal, but that won’t stop you from getting some odd looks.

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