Battle of the green by Christopher Potter

Battle of the green Designed by Christopher Potter. Printed at UWE Bower Ashton. Typefaces: Publico (headers), Azo Sans (body). Printed on GF Smith Extract Moon, GF Smith Colourplan Stone & Lockwood green, GF Smith Accent Smooth Ivory & Neenah Environment Birch.

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Foreword

We have a deep-rooted connection with ancient and veteran trees. We hug them, name them and recognise them as landmarks, and they feature in the memories and stories passed on through generations. They are iconic, natural monuments as significant as, and sometimes older than, cathedrals and stately homes. Ancient and veteran trees are of incredible importance for wildlife ; each tree is an ecosystem in its own right, providing a range of specialist habitats for animals, plants and fungi that depend on conditions found in the decaying wood, sap runs, cavities and crevices.

Battle of the green

Chapter one

Oa k

Bio div er sit y

on : 31 Carb ring Sto

Import ance : 3

Hazel: 23

Ash: 21

Tr ee s

ots Sc

9 e: 1 Pin

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Th re 45

iew rv e t

ndrew Weeding: 4 h A 1 t i w

s: at

Chapter two

67 e: ng a Ch

Loss: 3 5

g Laws: 49 Fellin

H u m an d

nt: me lop ve De

C l im a

Disease : 63

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Chapter three

Re-Growth: 69 Leigh Woods: 73 An interview with Forestry England: 79 What is being done to create new woodland for wildlife and people: 84 Re-growth in damaged woodlands: 85 Biosecurity in re-growth: 89 What needs to happen for regrowth: 94

Native woodlands are made up of native trees, these are the trees that colonised the UK following the last ice age. The UK’s native trees include English oak, Scots pine, hazel and ash.

Importance of native woodlands

The importance of native woodland told by Clive Anderson (Woodland Trust president)

Trees are all around us. Found in large numbers in woodlands and forests, or strung out single file along roads and railways, country lanes and city streets.

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Or decorating urban and suburban squares, parks and gardens. Everywhere they are a beautiful background to human existence. Once upon a time they were in the foreground of many people’s lives as well, providing a livelihood for foresters and foragers, farmers and families. Things aren’t quite so simple now, but we still depend on trees in any number of ways. Trees are multi-taskers, their leaves give us shade from the sun when it’s hot and shelter from the wind when it blows cold. Their roots keep fragile soils and river banks from being washed away. They filter the air, recycle the water and provide homes and habitat for wildlife. Nowadays it may happen on a more commercial basis, we still use wood from trees to make buildings and furniture and all sorts of objects great and small. And trees are a source of wonder and delight. Winter, spring, summer or autumn they provide the backdrop against which we measure the passing seasons, and they make us feel good. Even more than that, globally trees can play a vital role in the battle to avoid a climate catastrophe, if they are allowed to grow.

There is some good news to report. There are more woods and trees in the UK today than at any time in the last 100 years. But we remain one of the least wooded countries in Europe. And we keep losing ancient woodland – ecologically our most valuable resource. The past century has seen dramatic changes in the type, age, location and value of woods and trees. This has been in response to a host of factors which bring both risk and opportunity. Over the years our growing and largely urban population has developed ever changing needs from our land. Huge technological developments, an explosion in global trade, new transport links and climate change have all had their impact. Our remaining ancient woods and trees are those that have survived as the world has changed around them. Fragmentation of woods, loss of trees and the wildlife dependent on them has been brutal. The survivors that remain now form the backbone of plans for nature recovery. They are still some of our richest native habitats and provide the source of genetic material we will need to re-forest our landscapes.

with trees and woods. The role of trees in fighting climate change is now well understood. The challenge

Importance

We are on the edge of a new era of interdependency

is to find the space that trees need to expand and thrive across our nation. As they grow, the roots, leaves, trunks and branches of trees store carbon and, in doing so, they protect us from ourselves. A miracle of nature, a sprouting acorn can, in time, grow to become a mighty oak – one of the largest, heaviest and oldest organisms you will ever come across. As well as holding itself upright, an oak tree provides a lifeline to thousands of other species and forms a solid storehouse of carbon. We have the power to give trees the protection and care they need to survive and the space to grow to sustain and improve our landscapes and lives.

Oak Trees

Why are they important? The contribution of oak trees to landscapes, biodiversity,

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culture and economy is enormous. Renowned in history and legend, oak trees symbolise royalty, patriotism and strength. But perhaps their greatest feat is nurturing wildlife. They are a haven for a colossal 2,300 wildlife species, providing vital spaces to eat, shelter and breed. Even as a sapling, the oak provides food and homes for wildlife. As it grows it becomes more valuable, they develop cavities, crevices, dead wood and other features that allow plants and animals to flourish. Oaks become ancient trees when they reach 400 years old providing support for plants and animals that whole time.

Acorns After pollination, female flowers develop into a large shiny nut around 2-2.5cm long: an acorn. Held in a scaly wooden cup, young acorns start off green and can usually be seen from August, before maturing to brown and falling in autumn. Acorns are one of the main attractions when it comes to Oak trees for animals, they’re a favourite food of badgers, deer, wild boars, squirrels and wood mouse. They are also

Battle of the green

enjoyed by birds like the woodpecker.

Oak Flowers Male and female flowers grow on the same tree. Male flowers grow in long, dangly clusters and appear between April and May when they release their pollen into the air. The female flowers look like tiny red flower buds between the leaves and branches. Oak flowers are eaten by red and grey squirrels and many insects, including caterpillars and moths. The pollen is also a popular food source for bees, including the oakmining bee.

Importance

Oak Bark Oak bark is grey-brown in colour and smooth when the tree is young. As it matures, the bark thickens to become textured and rough with lots of creases and grooves. Eventually, pieces of bark will loosen and crevices and holes will form too, all providing niches for wildlife to

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shelter, feed and breed.

Oak Leaves Certain caterpillars feed exclusively I oak leaves. New leaf growth attracts aphids which then produce honeydew a substance that wood ants love to eat. This abundance of invertebrates attracts animals from higher up the food chain, like spiders and birds. In total oak trees support 38 species of birds.

Importance

Lichens, liverworts and mosses Oak hosts a huge 716 types of lichen of many shapes, colours and sizes which offer nesting material, food and shelter. Oakmoss lichen, as its name suggests, prefers oak. The rare Lecanactidetum premneae lichens tend to be found on trees at least 250 years old - usually the dry, brittle bark of old oaks. Rarer still are the 12 lichens that depend on oak alone, including Arthonia byssacea, Sclerophora farinacea, and Calicium adspersum. Liverworts, simple plants named because their leaf shape resembles the lobes of a liver, these include dilated scalewort and the delightfully named fairy beads. Mosses adorning oak’s bark and branches include cypress-leaved plait-moss (Hypnum cupressiforme) and slender mouse-tail moss (Isothecium myosuroides). Fungi play an incredibly important role when it comes to biodiversity. This is due to their extraordinary symbiotic

Battle of the green

relationship with trees and plants. This relationship,

which involves the colonisation of a plant’s root system by a fungus, provides the host plant with an increased transfer of nutrients and water, and the fungus with a transfer of carbohydrates.

Importance

Oak roots Oak roots are usually quite shallow, with most in the top 30cm of soil and extended well beyond the tree. The roots rely on a network of fungi called mycorrhizal fungi to gather more nutrients that the roots can’t reach, they have a symbiotic relationship with the tree that helps keep both species healthy.

Deadwood

Battle of the green

As a tree becomes older, it gradually dies. The trunk thickens and the innermost heartwood decays and becomes exposed, helped along by animal damage, weather extremes and specialist fungi. One of nature’s essential recycling processes, dead and decaying trees are a vital part of a wood’s biodiversity. It provides sustenance, nutrients and shelter for numerous species of forest animals, plants and fungi. twhich are more stable, moist and sheltered than most surrounding habitats.

19 Battle of the green

Scots Pine

Towering in the glen, the Scots pine is a truly stunning tree. It is one of only three native conifers, and our only native pine. It’s the perfect home for iconic Scottish wildlife, such as the red squirrel, capercaillie, Scottish crossbill and the Scottish wildcat.

Scots pine is the only truly native pine in the UK.

Importance

Where to find Scots pine:

It thrives in heathland and is widely planted for timber, but is also found in abundance in the Caledonian pine forest in the Scottish Highlands.

Value to wildlife: The Caledonian forest is a priority habitat under the UK Biodiversity Action Plan and is home to rare species such as the creeping lady’s tresses and lesser way blade orchids; the Scottish wood ant and Rannoch looper; and the capercaillie, crested tit and Scottish crossbill. Mammals include red squirrel, pine marten and Scottish wildcat. Scots pines in southern England are also the main caterpillar foodplant for the pine hawk-moth.

Ash One of our most beloved trees. Ash is one of the most common trees in the UK, but as ash dieback sweeps through, is it set to be erased from our countryside? When fully grown, ash trees can reach a height of 35m. Tall and graceful, they often grow together, forming a domed canopy. The bark is pale brown to grey and fissures as the tree ages. The tree is easily identified in winter by its smooth twigs that have distinctive black, velvety leaf buds arranged opposite each other.

Where to find ash: Ash thrives best in fertile, deep and well-drained soil in cool atmospheres. It is native to Europe, Asia Minor and Africa and is also found from the Arctic Circle to Turkey.

Battle of the green

It is the third most common tree in Britain.

Value to wildlife: Ash trees make the perfect habitat for a number of different species of wildlife. The airy canopy and early leaf fall allow sunlight to reach the woodland floor, providing optimum conditions for wild flowers such as dog violet, wild garlic and dog’s mercury. In turn, these support a range of insects such as the rare and threatened high brown fritillary butterfly. Bullfinches eat the seeds and woodpeckers, owls, redstarts and nuthatches use the trees for nesting. Because the trees are so long lived, they support deadwood specialists such as the lesser stag beetle. Ash is regularly accompanied by a hazel understorey, providing the ideal conditions for dormice. Ash bark is often covered with lichens and mosses. The leaves are an important food plant for the caterpillars of many species of moth, including the coronet, brick, centrebarred sallow and privet hawk-moth.

Importance

Hazel

Catkins resembling lambs tails, and late-summer nuts. Hazel is one of the most useful trees for its bendy stems and as a conservation saviour.

Battle of the green

Hazel is often coppiced, but when left to grow, trees can reach a height of 12m and live for up to 80 years (if coppiced, hazel can live for several hundred years). It has a smooth, grey-brown, bark, which peels with age, and bendy, hairy stems. Leaf buds are oval,blunt and hairy.

Where to find hazel: Hazel grows across much of Europe, parts of north Africa and western Asia. In the UK it’s often found in the understorey of lowland oak, ash or birch woodland, and in scrub and hedgerows.

Value to wildlife: Hazel leaves provide food for the caterpillars of moths, including the large emerald, small white wave, barred umber and nut-tree tussock. In managed woodland where hazel is coppiced, the open, wild-flower-rich habitat supports species of butterfly, particularly ground-nesting birds, such as the nightingale, nightjar, yellowhammer and willow warbler. Hazel has long been associated with the dormouse (also known

Importance

fritillaries. Coppiced hazel also provides shelter for

as the hazel dormouse). Not only are hazelnuts eaten by dormice to fatten up for hibernation, but in spring the leaves are a good source of caterpillars, which dormice also eat. Hazelnuts are also eaten by woodpeckers, nuthatches, tits, wood pigeons, jays and small mammals. Hazel flowers provide early pollen as a food for bees. However, bees find it difficult to collect and can only gather it in small loads. This is because the pollen of wind-pollinated hazel is not sticky and each grain actually repels against another. The trunks are often covered in mosses, liverworts and lichens, and the fiery milkcap fungus grows in the soil beneath.

Oaks have a

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huge 25

significance for biodiversity, numbers from the research published by the UK centre for Ecology and Hydrology.

Biodiversity The UK's native woods and trees are incredibly biodiverse. They support many different species of fungi, lichens, mosses and plants, as well as birds, invertebrates and other animals. Many of these species are threatened and becoming rarer. Some have already become extinct. But why are native woodland ecosystems so vital for biodiversity?

A lot of the native trees arrived in the UK over 10,00 years ago when the ice sheets retreated. Other plants and animals colonised the UK at the same time and therefore formed close relationships with these species.

Studies have shown that even just two oak species support 2,300 species of mammals, birds, invertebrates,

Importance

Using them for food, breeding sites and shelter.

fungi and mosses. 326 of these are highly specialised to rely on oak trees. One group of specialist woodland species, known as saproxylic invertebrates, depend on dead and decaying wood. Of 1,005 beetles known to use trees, over two thirds use decaying wood – particularly that found in large, old, native broadleaved trees in parks and wood pastures. There was a study in 2019 led by Richard Ennos that concluded that the UK’s native trees have the potential to adapt to future conditions, including those expected due to climate change.

27 Battle of the green

species supported by oak

Importance

00 Photo by Philip Pilz

A multitude of empirical and theoretical

efficient for harvesting, it is interesting

studies have found that high species diversity

to note that a diverse forest will grow faster

within an ecosystem gives it more stability

and sequester more carbon. This means that

in the face of fluctuating environmental

there is an economic value to biodiversity

conditions. This is particularly true of

for its own sake as well as for the resilience

assemblages of native species because such

it provides to other ecosystem services, and

ecosystems demonstrate a high degree of

it is essential that we preserve and restore

complementarity, where there is a complex

our native biodiversity.

balance between species that have evolved alongside each other. In other words varying

Though it is not just native woodlands

environmental conditions will favour different

that provide support for biodiversity.

species at different times. This means that

While monoculture plantations are not good

if one species is struggling, another with

for biodiversity, non-native species can still

a similar ecological niche may be more

be good for biodiversity as long as it isn’t

successful and will keep the ecosystem

a monoculture. There are certain birds that

functioning. A wide range of native species

are conifer specialists for example crossbills,

can even counteract the appearance

siskins, redpolls, goshawks, and crested tits.

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of an invasive predator such as the Nile

perch in Lake Victoria, although additional

However conifer plantations are associated

environmental pressures can lead to a tipping

with a lower ground flora diversity due

point that results in ecosystem collapse.

to the thicker canopy density. Also as generally conifer plantations are planted at the same

Ecosystems with high biodiversity are also

time they are all the same age and age affects

about twice as productive as mono-cultures,

the biodiversity also. Having a variation in age

and this is also true of forests globally, where

of the trees increases the diversity of beetle

timber production is higher in diverse forests.

and bird species and improves the habitat

Although monoculture plantations are more

for reptiles.

326 species depend on oak for survival. 229 species rarely found on tress other than oak. Importance

Storing Carbon Woodland and trees are one of the best ways to remove carbon dioxide from the atmosphere. However, we do know how much carbon is currently stored in all of the UK’s existing woodland2 , but until now we were unsighted on how much carbon is stored in ancient woodland and its potential for further carbon capture. Calculating the amount of carbon stored in a woodland is a complicated process of collecting data to be able to do the sums. The data needed includes, data on the woodland area and the woodland characteristics, to get this data you would need access to the SCDB (sub-compartment database) and the NFI database which is for private forest estate. Combining these two databases enables the estimates of total carbon to be split between two broad ownership categories. Estimates are given in millions of tonnes of carbon (MtCOe)

Battle of the green

Carbon is defined as carbon stored in all living plant material in both the above and below ground parts of trees that have a mean diameter of 7cm or more. This includes major roots, stumps, stems, branches, twigs and foliage. The estimates do not include carbon in young trees that have not grown to this minimum mean diameter, nor carbon in the stems of coppice that are harvested before reaching this minimum mean diameter. Also excluded is carbon in standing dead trees, growing saplings and seedlings, shrubs, other ground layer vegetation, lying deadwood, litter, soil, harvested wood products and substitution effects.

What does this tell us? The total amount of carbon in ancient and long established woodland sites across Great Britain is estimated to be 77 million tonnes, this includes 40 million tonnes in England, 27 million tonnes in Scotland and 10 million tonnes in Wales.

Why does this matter? This data shows us the strong evidence of the undervalued role that ancient woodland plays in Britain’s carbon balance. Ancient woodland has a disproportionate role in storing carbon compared to other woodland types. Ancient woodlands can store larger amounts of carbon due to their larger number of older trees and generally larger trees than other woodlands. These carbon stocks are not static, they are projected years as they continue to trap and store carbon in both younger and older trees.

Importance

to double in ancient woodlands over the next 100

Although ancient and long established woodland in Britain makes up only 25 percent of all woodland, it holds 365 of all woodland carbon in living trees.

“The total amount of carbon in ancient and long-established woodland across Great Britain is estimated to be 77 million tonnes.” Battle of the green

Woodland Trust

Loss of native woodlands

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“We’re suffocating ourselves by cutt ing th i

ng s

And the awful thing is that the knowledge is there.”

Loss

w do n

-Sir David Attenborough

39 Battle of the green

Loss

Ancient woodland is widely recognised as a valuable habitat, yet 85 per cent has no legal protection. As a result it is constantly under threat, particularly from development. Many ancient woods are islands within a hostile landscape of intensive agriculture and urban development, and most may be too small Another problem is overgrazing by livestock and deer.

Loss

to sustain viable populations of many woodland species. Climate change will lead to changes in temperature and rainfall, which may have a dramatic impact on our native woodland and it is inevitable that species will become extinct and that habitats will alter in response to these climatic changes.

An interview with Andrew Weeding Arborist

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How would you best explain your job? The job of an arborist is to manage the relationship

What happens with most of the trees you cut down?

between trees and humans in an urban environment.

Generally it all gets chipped and sent

To keep the risk levels of having mature trees at

to biomass energy plants, some gets

a suitable level through pruning over reaching limbs,

turned into fire wood and some

giving young trees good growth patterns through

is milled for furniture.

formative pruning, managing the size of trees in tight spaces through regular reductions.

Could you give an example of a recent job that was interesting?

What is the reason for most of the trees that you cut down? Is it disease, cut backs etc?

Recently we had to prune a larger

We have been cutting down a lot of ash trees due to ash

decay in the main stem (found

die back, which has been leading to large limb and whole

using a picus test which uses

tree failure.

testing the resistance of a fine drill

mature copper beech that has

bit into the wood to determine the

Do you have to cut down many native trees compared to non native?

soundness) it was decided that the

We cut down more non native trees than native , we try

if the limb weight was reduced

to only cut down native tree when they have disease/ its

and cable bracing was installed

the last option available.

to minimise impact if a limb was

tree was safe enough to be retained

too fail.

How important do you think native trees are compared to non native? Native trees are more important because they grow slower and stronger than non native trees, they are generally more resistant to pest and disease and they create habitat for a far larger range of species

Loss

43 Battle of the green

Loss

Threats

Our woods and trees are facing a huge array of threats, there are five key drivers of harmful change in the ecosystems: changes in land and sea, direct exploitation of organisms, climate change, pollution, and invasive

Battle of the green

species. UK woodlands are suffering, built development and transport infrastructure are still resulting in the loss of precious ancient woodlands and further fragmenting semi-natural habitats. Climate change is impacting on the timing of nature’s seasonal events, and invasive pests and disease are killing trees and altering native woodland composition. Measuring these threats is difficult, and most of them effect native woodlands in various ways. Therefore we must draw on multiple sources to gain a better understanding of the threats that the native woodlands face. Ancient woodland in Britain is being felled at a rate even faster than the Amazon rainforest reports the Guardian. However it’s far more complicated than that. Though almost half of all woods in the UK that are more than 400 years old have been lost in the past 80 years and more than 600 ancient woods and now threatened by new roads, electricity pylons, housing and airport expansions. Britain’s native woodlands are in a sorry state with just 7% in good condition and many suffering from these threats stated above.

Loss

With each ancient woodland lost, we lose a part of our cultural

heritage and the special wildlife that depends on it.

Felling Laws

Historically most of the county’s woodlands would have been managed either as coppice, wood pasture or high forest subject to selective felling under

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shelter-wood or group felling systems. In the industrial period the demand for pit-wood and competition from coal as a fuel led to coppice systems being abandoned and some woodlands being clear-felled and replanted. In the twentieth century some woodlands were felled during the first and second world wars and abandoned to regenerate naturally. Later in the century others were felled and replanted with commercial species. The management of native woods today should aim either to maintain the natural conditions of ‘wild’ woodland through minimal intervention, or the semi-natural conditions created by traditional forms of management - high forest, coppice or wood-pasture. Heavily modified or replanted native woods may need more active restoration.

Felling Licences apply only to trees with a stem diameter greater than 8cm or coppice wood with a diameter of greater than 15cm, and they impose no controls on the lopping and topping of trees. As a result, it is entirely legal to remove all the young trees, shrubs and undergrowth from ancient woodland, severely damaging their ecology. It is also legal for timber that would normally come under felling licence

Loss

a woodland owner to fell up to 5 cubic metres of control, every quarter, without a felling licence. If this allowance is taken up and regeneration of new trees is prevented by sheep or deer overgrazing, for example, it is only a matter of time before a woodland is degraded and disappears.

51 Battle of the green

It is only a matter of time before a woodland is degraded and disappears.

Loss

53 Battle of the green

Human Development

By the mid-20th century, the majority of ancient woodlands had been cleared to make way for human development, agriculture, or commercial forestry. Developments, such as roads, railways, housing, agriculture and leisure activities, can destroy ancient woodland, both directly through conversion the woodland.

Loss

of land use and indirectly through damage to

Large infrastructure projects, such as the High Speed 2 rail network, are considered as “wholly exceptional” under these policies on the basis that “the public benefit would outweigh the loss or deterioration of habitat”. As well as those woods subject to the ‘wholly exceptional’ clause, there are still many ancient woodlands under threat from indirect impacts as well as poor application of national and strategic planning frameworks by local planning authorities. Development can impact ancient woodland either directly or indirectly. Direct loss refers to actual removal of trees and vegetation and a change of land use. Indirect loss is much more insidious: pollution in the form of noise, light, dust or chemicals gradually alters the conditions of the wood, affecting its plants and other wildlife. Fragmentation is another form of indirect loss, as it can cut woods off from each other, thereby preventing the movement of species to and from the wood.

Country breakdown of ancient woodlands under threat from development that have either been saved, were lost, or are still currently under threat. Country

Saved

Lost

Threatened

England

743

612

800

Scotland

102

270

274

Wales

337

149

Northern Ireland

Total

1,186

981

1,225

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Top six threats: number of ancient woodlands saved, lost or currently threatened by threat type.

Threat type

Saved

Lost

Threatened

Site allocations

369

108

362

Housing

267

345

178

Roads

146

144

Agriculture

143

Electricity/Gas/ Water

131

140

Railways

108

Source- Woodland Trust

Woodland coverage in the UK

Loss

What does this tell us? Since the 1999, as of July 2020, 1,225 ancient woods are currently under threat from development, while 981 are known to have been permanently lost or damaged. On a more positive note, over this period 1,186 woods are known to have been saved from development threats – at least for now. Almost two thirds of all historic cases of woods under threat are from England, and this is still the case with current woods under threat. This is despite the protection afforded to ancient woods in England since the National Planning Policy Framework was reformed in 2018. Evidence suggests that this is because although the number of applications threatening direct loss of ancient woods has decreased, the number of developments adjacent to ancient woods, which would cause indirect impacts, has increased by a corresponding amount.

Battle of the green

In England, 12% of the woods currently under threat are threatened by High Speed 2. Wales has a higher proportion of woods saved than lost, while the opposite is true in Scotland. The biggest current threat to ancient woodlands is from site allocations, which are areas designated by local planning authorities for residential and industrial developments. Planning applications for housing, roads, agriculture, utilities and railways pose the next biggest threats. Together, these six threats account for 80% of current woods-under-threat cases.

Before After

Loss

Irreplaceable ancient woodland(top image) remains under significant threat from direct loss due to road building (bottom image), which also results in indirect impacts to remaining habitat from noise, pollution and fragmentation. (Images from the woodland trust)

1,2

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an cie

nt s d o o e r w a

Loss

y l t n

r de un

e r r u

. t a e r th 60

61 Battle of the green

Why does it matter? Any loss of, or damage to, ancient woodland by development destroys irreplaceable wildlife habitat that is also of huge importance to our culture and heritage. Only a small extent of ancient woodland remains – just 2.5% of the UK’s land area. Many species of plants, animals and fungi are highly dependent on ancient woodlands due to the stable conditions they provide and their sheer longevity, which has led to intricate relationships evolving. These species often have poor dispersal ability, so do not colonise new areas readily, and due to their very specific requirements, they may be easily out-competed by more generalist species. Ancient woodlands are their stronghold and last refuge. Every ancient woodland impacted by human development reduces the area available for these species and threatens their survival. Add to this the importance of ancient woodland as a carbon store and its carbon sequestration potential, which will help mitigate climate change, and there should be no cause to destroy such Loss

a rare and valuable habitat. Although our ancient woodlands have existed for thousands of years, they have very rarely been untouched by people. They are the very definition of cultural landscapes, influenced by nature and people throughout history. Our ancient landscapes, including woods and wood pastures, are irreplaceable artefacts of history, culture and ecology overlaid and interwoven.

63 Battle of the green

Disease

Importing is one way that pests and

and bacterial species survive in a delicate

disease reach our shores. For example oak

ecological balance within woodlands.

processionary moth can defoliate oak trees, but

This balance can be significantly disturbed

can also cause severe allergic reactions when

when a new species is introduced into this

they come in contact with people and animals.

system. Non-native ‘exotic’ species can be

This pest started causing problems with oak

a particular problem because the plants

trees in northern Europe in the early 2000s.

present in woodlands will not have co-evolved

However the UK continued to import oak trees

with these recently introduced species and

and therefore oak processionary moths are

will, therefore, not have any natural defence

now widespread. Despite this, these pests

against them. The predators that keep

have been imported as close as 2019.

Loss

Trees and other plants, fungi, insects

these exotic species in check in their natural range may also not be present. In these

The scientific community is only recently

circumstances, pest and disease outbreaks

starting to elucidate the full effects of tree

can have an extraordinarily

disease outbreaks on the wider environment.

severe impact.

Species such as ash and elm host many hundreds of species of insects, fungi, mosses,

Importantly, once a new pest or disease

lichens, birds and mammals, many of which

species becomes established, it can never

only survive on these specific tree species.

be removed. Detrimental changes are often

As a result of the dependency of these species

at a landscape scale as we have seen

on ash it is becoming increasingly clear that

with Dutch elm disease, ash die-back.

there is a real risk of an extinction cascade

These changes have wide-ranging impacts

event due to ash die-back.

on species that rely on the host tree species and so impacts are often under-acknowledged.

The impact of pests and diseases is

In addition, many of the diseases that have

predicted to become more serve under

become established over the last 30 years

climate change conditions. This area of

that are attacking native tree species

research is in its infancy; however, forest

are poorly studied so their wider impact

ecosystems will undoubtedly be affected

is uncertain.

by the combination of climate change and pest and disease introductions.

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“There are many more global pests and diseases which would cause devastation if they reached the

UK” Loss

Woodland Trust 66

Battle of the green

Climate Change

Accelerated climate change is widely

Not all species respond to temperature changes to the

recognised as one of the greatest

same degree, which can cause a ‘mismatch’ in the timing

threats to natural systems across

of food availability between different levels of food

the globe. There is substantial

chains. Changes to the timing of tree leafing have been

evidence that the UK climate

shown to have repercussions further along the food

is already warming as well as

chain. Oak-leafing records used to investigate the impact

projections of milder, wetter

of warmer springs on the tree-caterpillar-bird food chain

winters and hotter, drier summers

showed that in warmer springs oaks leaf earlier, which

during the 21st century

correlates with an earlier peak in caterpillar abundance. This creates a mismatch with breeding birds, such

The UK spring Index is calculated

as blue tits, great tits and pied flycatchers, where chicks

annually, it’s specific purpose is to

hatch too late to take full advantage of peak caterpillar

highlight a biological response to

numbers. There was also variation in the extent of the

climate change. The Spring Index

mismatch between the three bird species as some were

has become on average 8.4 days

less able to adapt by shifting their breeding phenology.

earlier, this causes several problems

The ‘normal’ timing of these events has been found to

to both animals and to trees.

have a positive impact on both the quality and quantity

Climate change, through altering

of chicks produced. This negative effect on breeding

tree phenology is having a negative

success is a clear example of how climate change altering

effect on breeding

tree phenology may lead to population decreases caused by mismatched timing higher up the tree food chain.

What needs to happen? More climate impacts research: the Nature’s Calendar dataset is a valuable tool for continued research on the impacts of climate change on phenology. The significance of climate change as a threat and driver of change to woods and trees warrants continued wider research which integrates climate Loss

and ecological sciences. Action to tackle climate change: without concerted action to address climate impacts, mismatch in breeding success and higher prevalence of pests and diseases threaten woodland wildlife.

Regrowth of native woodlands

Battle of the green

New planting in the UK

Data from the forestry comminsion

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As has been shown a lot of damage has been done. There is lots being done to help the re-growth of native woodlands, though far more could be done to help.

Two woodlands in one: Leigh woods The wall which runs through Leigh Woods was built in 1813 as part of an Act of Parliament for enclosing lands in the Parish of Long Ashton. The two adjacent estates have - until recent times - remained fairly intact, although parts have from time to time been leased for stone and timber. This dual ownership and consequent management is reflected in the present composition of the woodland.

The northern half of Leigh Woods The northern half was historically managed as coppice with standards. Though this hasn’t been actively coppiced on a large scale for nearly 100 years.

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Consequently, it now has a closed structure and a good proportion of old trees and dead wood. The canopy is dominated by mature and overmature oak standards with younger ash, birch. Old coppice stools of large outgrown oak, ash and small-leaved lime make up a significant proportion of the canopy.

There is a varied understorey of coppice hazel with field maple, holly, dogwood, hawthorn, spindle, and guelderrose. Where the soils are thinner, yew is locally dominant.

The southern half of Leigh Woods The southern part was formerly wood pasture and many of the veteran pollards, predominately oaks, have survived. A survey of the National Nature Reserve (NNR) found just under 300 Old Pollards. This area was historically part of the Ashton Court Estate, a Site of Special Scientific Interest (SSSI), to the west. These two sites have one of the largest populations of veteran trees in the South West. The pollards are home to rare and uncommon wood decay fauna, while the woodland has a good mix of canopy species with areas of ash, beech, oak and occasional cherry, field maple and small-leaved lime. There are also small but important areas of herb-rich limestone grassland which is notable for the presence of several rare and scarce plants. Re-growth

Recently the decision was made to managed all of Leigh woods as an SSSI, this will allow re-growth and development for native trees within the woodland which for a long time has been occupied by non-native conifer trees.

As mention before Leigh woods is co-managed and split into two parts by the parish wall. The northern part of the woodland is managed by Forestry England, where part is managed as an SSSI and the rest has been used for logging in the past. The southern part of the woodland is managed by the National Trust where the woodland and pastures are maintained for

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walkers and cattle.

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77 Battle of the green

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Trees standing tall by where the recent felling was, this is part of the area that will be regrown with native trees.

An interview with Forestry England About the change in application at Leigh Woods

Why did you cut down these trees? This part of Leigh Woods shows evidence that trees have been growing here since at least 1600AD. Some of the woodland has been replanted with non-

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native trees and some has developed more naturally. As part of our longterm management plan for Leigh Woods, we clear-felled this area of nonnative conifer as the first step to restore this area to native woodland.

Where did this wood go? The tree here included several conifer species. This softwood timber is used for construction materials and fencing, which locks up the carbon in the tree as long as the timber is being used.

What will happen here next? This area of the forest is part of the Avon Gorge Site of Special Scientific Interest (SSSI). This is a protected area of diverse habitats scarce wildlife species, and rare trees and plants — some of them aren’t found anywhere else in the world. Only half of this area falls within the SSSI, but we will manage the whole space to favour these important species and develop habitat.

Will you replant the area? We will replant this area with native broadleaf trees, including small-leaved lime grown from seeds collected right here, in Leigh Woods. The see will be grown in a specialist nursery for around two years. Before planting, we will clear the conifer brash (leftover branches and deadwood) into piles. This will expose bare soil to help plants to seed, and will be ready for our young trees to be planted.

“This is a protected area of diverse habitats scarce wildlife species, and rare trees and plants , some of them aren’t found anywhere else in the world.”

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Photo by Jestine Jenkins

81 Battle of the green

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Both planting and natural regeneration will be needed to reach aspirations for new woodland cover. 82

83 Battle of the green

What is being done to create new woodland for wildlife and people?

Trees and woods also perform

to development and other land uses, and to threats

a range of ‘services’ for people,

such as disease, result in habitat fragmentation and

the need for which is growing.

compound the creation challenge. A large portion

They capture carbon, mitigate

of the UK’s woodland now exists as small and scattered

the impacts of increased summer

patches, often surrounded by land uses that are

temperatures and help manage

inhospitable to wildlife. In England for instance, around

the increased risk of flooding.

75% of all woods are less than 10ha in size.

Additionally, they are a vital part

Wildlife in small woodland fragments is vulnerable

of our social and cultural landscape,

to local extinctions and will struggle to adapt to climate

providing opportunities for

change and other pressures. There is an urgent need

recreation and improved well-being,

to make small woodlands bigger and connect them

are treasured for their beauty, and

within networks of other nature-friendly habitats,

fundamental to making our towns

as highlighted in the Making Space for Nature report.

and cities liveable.

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Historic and continued losses of woods and trees

We can then begin to reverse the collapse of biodiversity and create opportunities for species to adapt.

Re-growth in damaged woodlands

What do we already know?

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Ancient woodland is irreplaceable

and where degraded, must be

Restoration aims to develop future ecosystems with

restored. Restoration of ancient

greater ecological integrity and resilience, and not

woodland in the most critical or

return woodland to some previous composition.

threatened condition is an urgent

It is important that the current state of most ancient

priority. The longer remnant

semi-natural woodlands is not seen as the pinnacle

the more likely they are to be

of ecological condition. Restoration is not complete

permanently lost. While urgent,

when tree species composition becomes native;

restoration also takes time.

ancient woodland restoration goes beyond addressing

Gradual restoration of Plantations

threats such as non-native conifers, and includes other

on Ancient Woodland Sites

positive steps towards maximising the ecological

through thinning and continuous

integrity of all ancient woodland sites. It is vital to track

cover transformations requires

progress with the restoration of the most critical and

regular and ongoing management

threatened ancient woodland ecosystems, to avoid

interventions to achieve the desired

the deterioration or loss of remnant ancient woodland

regeneration and wider recovery.

features from inaction or inappropriate management.

Long-term vision Ancient woodland restoration requires a long-term vision. It is vital that restoration is not just seen as addressing the negative impacts, or considered complete when tree is required to improve ecological integrity. This requires positive steps to develop other aspects of woodland structure and composition. For example, the need

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species composition becomes native – further action

to develop more decaying wood and veteran trees, and to reduce the impacts from nitrogen air pollution, and the vital contribution of new woodland.

“Wider paths and rides, with their higher light levels, are often where woodland flowers survive and provide a source of colonisation into stands formerly dominated by shady conifers”

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Woodland Trust

What needs to happen? Policies and targets: forestry and biodiversity policies must be strengthened, with specific commitments and quantified targets for ancient woodland restoration across the UK. Progress should be informed by assessments of condition rather than canopy cover composition alone.

Regulation and standards: consideration should be given to a legal standards (e.g. UKWAS), requirements must be better verified through clearer mapping and monitoring of remnant features in particular.

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requirement to ensure ancient woodland restoration. Within existing

Public forest estate in active restoration: government bodies manage a large percentage of the UK’s PAWS and have a duty to lead restoration and demonstrate exemplary practice. This requires better understanding of progress with restoration and the management approaches used.

Biosecurity in re-growth

Home-grown tree saplings for planting schemes avoid the need to import plants and any harmful diseases they may harbour. Locally collected seeds are also more likely to produce trees adapted to locally prevalent pressures such as tree disease or drought and they will flower and fruit in season with local pollinators and other wildlife – unlike many imported plants. UK and Ireland Sourced and Grown (UKISG) is currently the only biosecurity assurance scheme that tackles the significant pest and disease risk posed by the importation of plants. There is a clear link between the increased use of imported plants since the early 1990s and the rise in new tree pests and diseases. When it became clear that ash dieback had been imported into the UK on infected ash saplings that were planted out into the wider environment in 2012, the Woodland Trust decided that none of the trees

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it planted would be imported. The plant production industry is in the process of introducing a new plant health standard, Plant Healthy. This voluntary standard aims to raise awareness of biosecurity issues across the industry through the introduction of new checks on production processes. Plant Healthy does not prevent the importation of plants but it does check the plant health chain of custody (plant passports and phytosanitary certificates). As the standard develops it is hoped that it will provide a more biosecure plant supply chain.

What does this tell us? Twenty-six UK tree nurseries have now adopted the Woodland Trust-initiated assurance standard, UKISG, for some or all of their tree stock. To date the Woodland Trust has procured 12.5 million UKISG trees and has contracts in place for a further 14.5 million trees until 2024. This has eliminated the risk of introducing pests and diseases to the UK from what could otherwise have been 27 million imported trees. In addition, the threeyear contracts provide security and confidence to those nurseries awarded a tender and the Woodland Trust provides business to other nurseries on an opportunistic basis, where they meet the UKISG assurance standard. Given the success of UKISG and the willingness of nurseries to be involved, it is estimated that the current 26 assured nurseries could produce 70-100 million UKISG trees per year.

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Why does it matter? Widespread uptake of the UKISG assurance scheme with UK nurseries demonstrates the demand for biosecure and well-adapted tree stock in planting schemes, while supporting UK business

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and creating jobs.

What needs to happen to help biosecurity? Greater uptake of UKISG: biosecurity and resilience of UK trees depends on all planting schemes having access to disease-free and well-adapted planting stock i.e. UKISG or similar assurance standards. This should include all procurement of trees by governments, e.g. for large transport infrastructure schemes.

including tighter regulations and a major education programme for those buying and selling young trees, including within the horticultural sector.

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Reduce imports: reduce the demand for, and use of, imported stock,

Sustainable supply chains: develop sustainable seed stands, collections, storage and supply chains as a matter of urgency to meet forecasted need for tree-planting material. This should include support for community tree nurseries to ensure availability of tree stock close to where the planting is planned.

Promote natural regeneration where appropriate: managing trees to selfseed and naturally spread can be a suitable way of creating new woodland in many circumstances, avoiding the need for planting altogether.

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What needs to happen for regrowth No further loss: there should be no further loss of ancient woodlands. In order to achieve this, opportunities to strengthen their protection must be taken. Giving them full legal protection should be explored in recognition of their immense value that cannot be recreated or replaced.

Watertight national policy: government policy must be strong and clear on when development is acceptable or not, and well-enforced with support for local planning authorities. Action to enable the economy to recover from Covid-19 must not mean deregulation that further jeopardises existing protections.

Improved ancient woodland inventories: up-to-date/complete inventories of ancient woodlands across the whole of the UK are needed to be able to identify all ancient woodlands and protect them (including those under 2ha which have been excluded in the past).

Transparent monitoring: threats to ancient woodlands from planning applications, and loss or damage, should be reported by statutory nature This is currently being undertaken by the Woodland Trust, a charity with limited resources, that is not a statutory consultee.

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conservation bodies to provide a full and clear picture across the UK.

More research: developers often apply a 15-metre buffer around ancient woodlands, but more research is needed on what buffer sizes are best to protect ancient woodlands from nearby developments.

References https://www.woodlandtrust.org.uk/blog/2020/07/biodiversity-and-native-woods/#:~:text=Why%20 are%20native%20woods%20important%20for%20biodiversity%3F&text=The%20UK’s%20native%20 woods%20and,are%20threatened%20and%20becoming%20rarer. https://www.woodlandtrust.org.uk/state-of-uk-woods-and-trees/ https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/oak-tree-wildlife/ https://www.forestresearch.gov.uk/documents/7110/FCRP030.pdf https://www.woodlandtrust.org.uk/media/49731/state-of-the-uks-woods-and-trees-2021-the-woodlandtrust.pdf https://www.nationaltrust.org.uk/leigh-woods/features/the-history-of-leigh-woods https://moortrees.org/the-biodiversity-benefits-of-native-woodlands/ http://www.wbrc.org.uk/atp/Ancient%20Woodland%20Threats%20-%20Woodland%20Trust.pdf# https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/oak-treewildlife/#:~:text=Acorns%20are%20a%20favourite%20food%20of%20many%20animals.,Credit%3A%20Richard%20Faulks&text=Badgers%20feed%20on%20acorns%20and%20make%20 their%20setts%20beneath%20oak%20too.,-Credit%3A%20Kevin%20Keatley&text=Wood%20mice%20 enjoy%20eating%20acorns.,-Credit%3A%20(Photo%3A&text=An%20enormous%201%2C178%20 invertebrate%20species,rely%20solely%20on%20this%20tree. https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/a-z-of-british-trees/scotspine/#:~:text=It%20is%20thought%20that%20in,the%20national%20tree%20of%20Scotland. https://www.woodlandtrust.org.uk/plant-trees/advice/how-to-plant/ https://www.woodlandtrust.org.uk/plant-trees/advice/where/ https://www.woodlandtrust.org.uk/plant-trees/advice/choose/ https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/a-z-of-british-trees/ ash/#:~:text=Value%20to%20wildlife,wild%20garlic%20and%20dog’s%20mercury. https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/a-z-of-british-trees/ hazel/#:~:text=Value%20to%20wildlife,species%20of%20butterfly%2C%20particularly%20fritillaries.