When is a woodland a wood?

Mark Antcliff – Woodland Officer

The National Park Authority has played a role in creating more than 600 hectares of new native woodland since the turn of the century, with something in excess of half a million trees established.

But when is a new woodland actually a wood and how do you measure the success of a habitat created?

In terms of tree growth the first milestone is when the young trees are fully established and have outgrown the competing vegetation and the attention of voles, rabbits, deer and livestock and their teeth. The second is when the branches of the new neighbouring trees meet – this is called “canopy closure” – from which point the ground flora will alter as shade tolerant and shade loving species will have better success, including our beloved bluebells. Perhaps a third is when the new trees reach a stage where they could be used to produce wood and timber through thinning or coppicing.

I was thoughtful of this question when revisiting a site that was planted about 16 years ago in Bilsdale. Here the area of an existing woodland had been extended by new planting, mainly young oak trees.Existing area of Ancient Woodland in Bilsdale. Copyright NYMNPA.

Contractors planting new woodland alongside the existing Ancient Woodland, back in 2001. Copyright NYMNPA.

There were some initial challenges caused by a faulty batch of plastic tree shelters that degraded faster than they should have leaving the new trees vulnerable. However the trees are now fully self-supporting and I can walk under them, which for me personally is a good moment as I can then consider myself in a wood rather than looking at it. The icing on the cake however is that some of the trees planted 16 years ago are now producing acorns, a sign that a true self-regenerating woodland has been created.

Part of the woodland planted approx. 16 years ago showing this year’s additional planting in the distance. Copyright NYMNPA.

Buoyed by such success we have, with the cooperation of the land owner and his agent, planted an additional area of 3 hectares this winter. I can’t wait to see how this new woodland extension looks in another 16 years’ time, alongside the ancient and post-millennial woods already in place.

As a Woodland Officer, I do tend to think in the long term.

Loving Levisham Estate: a personal view point

Rachel Pickering – Natural Environment Team Leader

Every day (when I am not at my desk) I take the dog for a walk past ‘the view point’ and every day I love it!  How could you not?

‘The view point’: view from Newton on Rawcliffe looking north east over Levisham Moor. Copyright Rachel Pickering, NYMNPA.

‘The view point’: view from Newton on Rawcliffe looking north east over Levisham Moor

My favourite version of the view is when the wisps of mist are still stuck to the trees in the valley even when the rest of the morning mist has long since left. I get to admire the landforms – Newtondale, the finest example of a glacial-lake overflow channel in England, carving through the striking two tiered moorland plateau. If I time it right I can hear and sometimes see a steam train chugging and tooting its way into Levisham Station down in the valley.

What makes this view extra special for me in particular is that it comprises part of Levisham Estate which I manage, alongside our Senior Ranger David Smith, for the National Park Authority. Between us we ensure that the Estate, which has been owned by the Authority since the 1970s, is managed for National Park purposes. As well as the stunning landscapes it boasts some outstanding wildlife habitats and a full range of archaeological curiousities including scheduled monuments.

It’s not just me that thinks its special. The majority of the Estate is designated as a Site of Special Scientific Interest (because of succession habitats, botany and geology), with the moorland also being designated as a Special Protection Area (because of merlin and golden plover populations) and a Special Area for Conservation (because of heathland habitats).

The majority of the Estate’s 3,358 acres are heather moorland but it actually includes a bit of everything. Here are a few of its gems:

Over the years we’ve been carrying out projects to conserve and improve the Estate. Here are a few examples of these:

Levisham Moor with heather in bloom. Copyright NYMNPA.

Improvements to the moorland grazing regime via a traditional Countryside Stewardship Scheme (2003-2013) and continued through the current Higher Level Stewardship agreement with the Commoners (Levisham Moor is Common Land).

Hole of Horcum following bracken control in 2015. Copyright/photo credit rjbphotographic.co.uk

Hole of Horcum area in 2015 showing positive results of bracken control . Bracken has also been specifically controlled on areas of high archaeological value at Rhumbard Snout and Dundale.

Carrying out scrub control at Station Field. Copyright NYMNPA.

Scrub control on wet grassland habitat at Station Field 2008.

Tree Planting, Hole of Hocum in 2011. Copyright NYMNPA.

Tree planting in the Hole of Horcum 2011 as part of the Slowing the Flow at Pickering partnership project.

Access improvements, Hole of Horcum in 2013. Copyright NYMNPA.

Access improvements being shown to National Park Authority Members – pitched path in the Hole of Horcum 2013.
Levisham Moor and the Hole of Horcum Walk

The Estate is a great place for volunteers to get involved. Over the last few years 4,000 of the trees planted are thanks to our committed volunteers. It has also proved to be a useful place for our Apprentice teams to practice their newly learnt skills including heather burning, bracken and scrub control, and fencing.

The Levisham Estate is a big commitment and a rewarding place for many people, not just me.

Footnote
I confess that I am feeling rather reflective at the moment as a couple of colleagues who have been working at the Park for even longer than me (over 18 years) are about to leave. I grew up near to Levisham Estate and have seen the changes close up, over time. A few years ago the following photos of ‘the view point’ were included in the ‘Now and Then’ photographic exhibition at The Moors National Park Centre, Danby. It was rather strange, but striking, that on the day I went to take the ‘now’ photograph there just happened to be four walkers sat on the bench. They were fascinated to see the level of change to the landscape and fortunately were very happy to be slightly rearranged to replicate the ‘then’ photograph.

The 'then' photo - looking down Newtondale, 1960s.

The 'now' photo - looking down Newtondale, 2012. Copyright NYMNPA.

A to Z: a multiplicity of Ms

M

MAGNETITE

As mentioned previously, in the 1850s a seam of iron rich ironstone was discovered in Rosedale. Also known as lodestone, magnetite had long been a valued mineral because of the amount of iron ore it contains, so much so that it is often magnetic.

Rosedale - copyright Colin Dilcock, NYMNPA

The discovery in Rosedale led to the rapid development and expansion of the mining and calcining industry there and in the wider area. There were great expectations …

“Professor Phillips delighted and informed the company by his description of the ‘Ironstones of Cleveland’ … The Rosedale band at its richest points, yielded 50 per cent [ore] and in many places 42 per cent. The Rosedale stone was magnetic and contained phosphorous, it was not merely magnetic, but it had an inherent magnetic polarity … There must spring up over the Cleveland district, through the working of the iron ore, great towns, with a numerous and active population; and, as a result, the moorland would be brought under cultivation and this once dismal tract of 20 square miles would rejoice in all the material means that could promote human happiness and prosperity…”

From a meeting of the British Association for the Advancement of Science at Leeds, as reported in the Manchester Courier and Lancashire General Advertiser, 2 October 1858.

However the actual magnetite seam was soon exhausted leaving the industry exploiting poorer ironstone and slowly declining into the 20th century. The magnetite proved to be rather a flash in the pan.

This Exploited Land of Iron logos

MESOTROPHIC LAKES

There are very few natural lakes in the North York Moors due to geology and climate, which makes Lake Gormire on the south western edge of the National Park even more remarkable. In the last Ice Age a hollow was formed by a meltwater channel between the edge of the moving Vale of York ice sheet and the edge of the North York Moors gritstone escarpment. The channel damned up and the lake left behind divided into two bodies of water – Gormire and the much smaller, Buttermere.

These are mesotrophic lakes – containing a narrow range of nutrients in medium concentrations. This type of lake chemistry is rare and becoming rarer as lakes are effected by artificially increased levels of nitrogen and phosphorus and so become eutrophic. Lake Gormire is surrounded mainly by semi natural woodland and fed by springs and so largely circumvents the risks of artificial diffuse pollution and nutrient enrichment.

Because of their chemistry Mesotrophic lakes can support higher levels of diversity of macrophytes (algae), aquatic plants, invertebrates and fish. The fen (‘mire’, ‘mere’) plants around Gormire/Buttermere reflect the acid soil, so there is Marsh cinquefoil Potentilla palustris, Common skullcap Scutellaria galericulata and Tufted loosestrife Lysimachia thyrsiflora, as well as Bog bean Menyanthes trifoliata and Water horsetail Equisetum fluviatile. Gormire is particularly popular with noisy water birds, mating toads and freshwater leeches, all exaggerating the primeval sense inside this Ice Age hollow.

Lake Gormire from Cleveland Way, north of Sutton Bank - copyright Mike Kipling, NYMNPA

Lake Gormire and the area around it is a designated Site of Special Scientific Interest. The cliff slope woodland above Lake Gormire is the Garbutt Wood Nature Reserve managed by the Yorkshire Wildlife Trust.

MILKY WAY

The Milky Way is a galaxy of billions of stars and planets sometimes partly visible to the naked eye as a milky looking band of light in the night sky.

Milky Way and Perseid Meteor Shower Sutton Bank - copyright Russ Norman Photography.

We’re in the middle of the Dark Skies Festival 2017 here in the North York Moors National Park. The dark skies over National Parks make it easier to see the lights of the galaxies around us. This February is particularly good for viewing Orion and also a very bright Venus.

February 27 1920   The mysterious stars

…Later in the evening a half-moon shone in a filmy sky across which, from S.E. to N.W., ran a Noë-ship of thin white clouds. A soft mist hung in the far valleys, but the nearer moory slopes loomed clearer. In the pastures the furze bushes were startlingly like huge black beasts grazing on the rimmed herbage. No sounds broke the utter silence of the moonlit hills; the wind had almost died away, but as I stepped over the little rill from Thunderbush Farm [Commondale], I heard its faint, musical ripple.

The ever-mysterious stars flashed through the interspaces of the filmy clouds and circled silently above the dim earth. Sirius flashed due south whilst mighty Orion hung high above the moor edge, his glory somewhat dimmed by the moon. What would life have been without the stars?”

A Man of the Moors: Extracts of the Diaries and Letter of Frank Elgee.

MINI-BEASTS

We use the term mini-beasts for the tiny invertebrates that go without notice until they’re looked at under the microscope and a menagerie of marvel and dread is revealed.

Identifying and counting river invertebrates is a very useful way of assessing the health of a river at a particular spot. Certain species indicate good water quality and others, poor water quality; a change in species/numbers indicate a change in water quality e.g. a pollution incident. There is a national programme of riverfly monitoring led by the Riverfly Partnership. Results are recorded centrally and indications of a potential incidents are reported to the Environment Agency. The National Park run a number of local Riverfly Monitoring Workshops for volunteers – the next one is 1 March.

MOSCHATEL Adoxa Moschatellina

Moschatel is a perennial unobtrusive plant which likes the damp, shady conditions found along woodland edges and on shaded hedge banks. It flowers between March and May, producing five lime green flowers on top of a leafless stalk, four flowers face outwards and one flower faces upwards, forming a cubic which has led to the plant’s other common name – Townhall Clock. The plant grows along the ground through rhizomes with the flower stalks growing up through its leaves to only c. 15cm tall. It is a common plant but easy to miss – look out for it in early spring before it gets hidden by taller plants.

Moschatel at Sieve Dale. Copyright Ami Walker, NYMNPA.

MOTTE AND BAILEY

Historic England suggest there are over 600 motte castles or motte-and-bailey castles in England. These were early medieval fortifications built by the Normans and made up of a large mound of earth/rubble (the ‘motte’) with a defensive palisade and tower on top, and an embanked enclosure with other buildings (the ‘bailey’) adjoining.

A motte and bailey castle could act as a fort when required as well as providing the residence for the local landowner/representative of the King and a centre for feudal power. They were often built on high ground to take advantage of the extra height to dominate the landscape and overlook access routes.

Soon after the beginning of Norman rule in England came the ‘harrying of the north’ – a military campaign to overcome and overwhelm the population in the north of the country and hammer home the idea that the Normans were here to stay. The new motte and bailey castles were a highly visible tool for holding that ground and reinforcing that message.

By the 13th century castle design had moved beyond the basic motte and bailey. Although the timber structures have largely gone, the earthworks are often still traceable in the landscape, and rubble mottes and the remnants of stone towers remain. Many are scheduled. Examples in the North York Moors include Hood Hill, Easby motte, and Foss Castle.

MOTHS

Moths are often considered the poor cousins of butterflies in the Lepidoptera family. The most obvious difference between butterflies and moths are that the former are active during the day whereas moths are mostly (but not all) nocturnal, feeding on the nectar of night blooming/night scented plants. Another difference is that when resting, butterflies usually close their wings whereas moths leave theirs open and this makes it easier to examine their intricate patterning and refined colouring. But as with most ecological questions – what is the difference between butterflies and moths? – there is no obvious answer and always an exception. Moths can be just as colourful, just as beguiling and just as in peril, as butterflies. For more on moth conservation see here.

Shandy Hall, Coxwold has become a location for moth study and reporting over the last few years. The gardens there provide a semi-natural/cultivated habitat for many species – over 400 different species have been recorded in the gardens to date.

Previously on the North York Moors A to Z … A, B, C, D, E, F, G, H, I, J, K, L

Ageing Mussels

Simon Hirst – River Esk Project Officer

As mentioned previously, the River Esk in the North York Moors is the only river in Yorkshire with a Freshwater pearl mussel population Margaritifera margaritifera. The population is estimated to be comprised of approximately 1,000 individuals and is in drastic decline, so much so that it is on the verge of extinction. The decline is due to a number of linked causes such as water pollution, choking of the river bed by sediment build-up, deterioration in fish numbers and habitat degradation.

A dense bed of healthy adult mussels in Scotland. Copyright Sue Scott - SNH,

We’re working to improve the riparian habitat and so help secure the local population of Freshwater pearl mussel in the River Esk. We recently sent a sample of mussel shells from the Esk* over to the Swedish Natural History Museum in Stockholm, in order to determine the age of the mussels in the River Esk. The maximum age of Freshwater pearl mussels in the wild has been shown to vary considerably, from a low of 35 years in Spain (warmer, lower latitude rivers) to over 200 years in arctic areas (colder and high latitude rivers). Information from the ageing study would tell us how long we have left to save the Esk population from extinction and help identify the approximate time when the River Esk mussel population went into decline.

Dr Elena Dunca from the Swedish Natural History Museum sectioned (cut though) the shells supplied and then counted the growth lines on the mussel shell using a high powered microscope.

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Growth lines visible on the freshwater pearl mussel shell.

Esk FWPM - Age and length graph - Swedish Natural History Museum

This age/length graph will allow us to age fairly accurately any mussels we find in the wild in the future just by measuring them.

A total of 10 shells were aged by Dr Dunca, and the graph below shows that the mussels sent to Sweden ranged in age from 45 to 88 years of age.  The mussels in the River Esk also showed normal growth rates.

Esk FWPM - Length frequency graph - Swedish Natural History Museum

Length frequency graph of mussels in the River Esk

The smallest live mussel we have found in the Esk up to now was 75mm (approximately 28 years of age). This means the last time the Esk mussels reproduced successfully in the wild was in the late 1980s. The largest mussel we have found in the Esk was 156mm (approximately 100 years of age), which means it was born around the time of the First World War. The vast majority of the mussels are around the 130mm-140mm size range (approximately 80 years of age). We now know for scientific certainty that the Esk has an ageing population in need of help!

The best hope for our mussels is for them to start to successfully reproduce again. We’re working with the Freshwater Biological Association (FBA) who are carrying out captive breeding work in the Lake District. We hope to re-introduce the captive bred young Esk mussels from the FBA Facility back into the Esk once the riparian habitat is restored enough to sustain them, and so ultimately stop this species from becoming extinct in the wild (of Yorkshire).

* Please note – No mussels were harmed in the making of this study! We used empty shells that were found on the banks of the Esk.

Thanks to our funders at Biffa Award, for their support to carry out this vital research work.

Biffa

Biffa Award is a multi-million pound fund that helps to build communities and transform lives through awarding grants to community and environmental projects across the UK, as part of the Landfill Communities Fund.

Revitalising the Rye

Tom Stephenson, External Funding Officer

There must be something in the water in the North York Moors, having just started delivering the This Exploited Land of Iron Landscape Partnership Scheme, the National Park Authority and its partners* have also been successful at the first stage of securing a further £2 million of Heritage Lottery Fund money to develop our next Landscape Partnership SchemeRyevitalise.

The River Rye and its tributaries rise on the moorland of the North York Moors, flowing through fast and clear upland becks that carve out steep sided dales until the land flattens and the river slows and broadens taking on the character of the undulating Howardian Hills and the flat lowlands of the Vale of Pickering. The Ryevitalise Landscape Partnership Scheme under development will help appreciate and enhance the Rye’s verdant landscape and clear waters which have been prized for millennia for their beauty and tranquillity resulting in a more natural, better functioning and better understood landscape.

Planned projects will cover four themes:

  • Water Environment, looking at aquatic habitats of the Rye and rare and threatened species;
  • Water Quality, working with land-owners and managers to reduce pollution;
  • Water Level Management, working alongside our delivery partners to harness natural processes to manage the sources and pathways of flood waters; and
  • Reconnecting People, improving the understanding of the river landscape by telling the story of its evolution and helping people to protect their heritage.

Without wanting to spoil the surprise of future blog posts, below are just some of the particular issues we are aiming to address through Ryevitalise scheme projects if we’re lucky enough to be successful in our Stage 2 application due in October 2018.

The wet…

Water is the major theme of Ryevitalise. Through the Ryevitalise scheme, from the high moorlands to the lowland wetlands, we will identify priority areas of riparian habitat for restoration to ensure existing high-value habitats (and their species) are in positive management and can act as nodes from which to extend outwards by creating ‘stepping stones’ and connections between these habitat sites.

Wetter still, we will assess the geomorphology and key features of the aquatic environment and target areas where aquatic habitats could be improved by creating changes to the channel through creating gravel bars, by placing debris to create slacks or by making changes to river bank profile. This work will include a survey of the habitats and species of the oxbow lakes in the lower Rye, and also the collecting and analysis of sediment cores to look for valuable paleoecological data which might shed light on how the local landscape formed.

The dry…

We have previously reported on the problems that fluctuating water levels in the River Rye
in Duncombe Park has on the White-clawed crayfish, the only native crayfish in the UK, White-clawed crayfish - during 2016 rescue in Duncombe Park. Copyright NYMNPA.which is suffering from a “perfect storm” of threats. Ryevitalise will prioritise protective measures for the existing population and carry out a feasibility study to identify where potential local ark sites might be located. Ark sites for White-clawed crayfish would allow populations to become established in isolation, separated from the threat of non-native crayfish and the crayfish plague they can carry.

The small…

Alcathoe bat. Copyright Cyril Schonbachler.One of the Rye catchment’s smallest inhabitants is the Alcathoe bat. Relatively new to science, having been first identified in 2001 and only recently becoming the latest addition to the UK bat family, this little creature has only been found at two other sites in the UK so far. Ryevitalise will seek to establish a deeper knowledge of where colonies of the Alcathoe bat and other key bat populations are, along with the requirements to support their survival.

The tall…

At the other end of the size spectrum and intrinsically linked to bats are some of the Rye catchment’s largest residents – its ancient and veteran trees. The area is a national hotspot for these giants that not only give an air of majesty to the landscape as living witnesses to history but also provide important habitat for many invertebrate species as well as providing important roosting sites for Rye bat populations.

The old…

Not only is the Rye catchment home to iconic built heritage like Rievaulx Abbey, Rievaulx Terrace, Duncombe Park and Nunnington Hall but it also contains a wealth of less obvious heritage that traces vernacular land use and tells the story of the working River Rye. Working with local history groups, Ryevitalise will record the remaining evidence of man’s relationship with the river over the centuries, surveying and recording the traces of the former agricultural and industrial settlements along the river banks. Accurate 3D models will be produced of the principal remaining watermills, iron working sites, water races and leats. Essential conservation and consolidation work will be identified from the surveys carried out.

The new…

Meanders in Rye near Sproxton - can see the water crowfoot beds within the river, September 2016. Copyright North East Yorkshire Ecological Data Centre.Like a lot of watercourses, it is not practical to access the river in its entirety at ground level. So as part of the Ryevitalise scheme an Unmanned Aerial Vehicle flight will record the entire 50km main river from its moorland origins all the way downstream to where it
meets the River Derwent. This will produce an invaluable record and will provide an insightful journey along the river for local communities, highlighting how this vital artery connects them all. Tailored sections of flight data will be made freely available to local schools, businesses, and community groups as a community resource; it will also form part of the scheme’s wider education programme.

We are all really excited about the next steps in developing the Ryevitalise scheme; the opportunity to make the most of the wealth of habitats, species and history surrounding the river; the potential to make a lasting difference to this wonderful landscape, and the chance to create a real splash.

HLFNL_2747

* Partners currently include East Yorkshire Rivers Trust, English Heritage, Environment Agency, Forestry Commission, Howardian Hills AONB, National Trust, Natural England, North Yorkshire County Council, Ryedale District Council, Woodland Trust, Yorkshire Wildlife Trust, as well as local communities.

A ‘Gothic’ icon

Ravens (Corvus corax) are a relatively common bird in some places. In the British Isles they currently breed mainly in the west and north. But they have been moving eastwards.

Single Ravens are now and again seen over the North York Moors. Excitingly, this summer saw the first breeding Ravens in the North York Moors for a long while, at least 50 years. Three chicks fledged.

Adult Raven near Ravenscar - copyright Graham Oliver, BTO.

The nest was near Ravenscar on the coast. Ravenscar and other places in the North York Moors such as Raven Hill, Raven Heath, Ravensthorpe, Raven Stones, Ravens Gill and Ravensgill Beck, usually share some kind of nearby cliff edge habitat (coastal or inland) where Ravens like to nest. The occurrence of these place names indicate that Ravens were more usual in the North York Moors in the past, so the fact that they have bred again in the North York Moors suggests a return and a boost to the natural heritage of the area.

These places were named so because of the presence of Ravens; Ravens have always been culturally significant. It’s not hard to see why. Their size, colour and sound is striking, but it is also their perceived cleverness, their carrion eating habits and their interaction with human society which gives them a special place in cultural history. Ravens have been loaded with superstitions and connotations. Wariness of the apparent watching and knowing nature of the bird causes unease. They are associated with premonitions of doom; seeing or hearing a Raven has been taken as a sign of imminent death. These dark associations continue, at least in part, today.

Raven - the Watcher by JestePhotography. http://jestephotography.deviantart.com/art/Raven-The-Watcher-532656250.

So in celebration of this age old cultural fear and to mark Halloween, here is an example of a local Raven tale. The lesson is – never look a Raven in the eye.

Some time ago a man was walking home over the moors.

It was already dusk but he didn’t mind because he didn’t have much further to go and he had made money that day.

He knew the way because he had walked it many times before. He counted the scarce land marks as he went till he knew there were only three more boundary stones to pass before the moors would give way to a gentler landscape and then it was only a few miles to his home.

As the gloom drew in he saw the first of the three boundary stones just ahead of him. A Raven was sitting on top of the stone. As the man went passed the bird didn’t fly away, instead it looked at him, cocked its head and called out in the silence

“Craaw craaw”
“Corpse corpse”

The man turned his head. The Raven still looked at him.

“Craaw craaw”

The man hurried on. He was starting to feel tired but he could see the glow of the lights of his village in the distance just over the horizon of the darkening moors. He thought about the warmth of his fire and the taste of his dinner.

It was getting colder and the greyness around him was turning to black. There were no stars in the sky, and he couldn’t see the moon. There were odd shapes on the moors, in the gloom – ancient silent burial mounds and twisted bitter rowan trees.

Just in front he saw the outline of the second boundary stone. There was a Raven sitting on top. The man didn’t look at it – he walked straight on, looking ahead. The Raven looked at him though.

“Craaw craaw”
“Corpse corpse”
“Corpse corpse”

The man pulled his coat around him. He didn’t know why he was mishearing the bird call. He tried to hum a tune, but he couldn’t think of one.

For a moment he thought about heading off the track to avoid the last boundary stone but he knew he couldn’t because then he would be lost. He thought about the people he’d heard of that had been lost on the moors and who had never got home.

He kept walking. He felt the damp blackness pressing about him. He couldn’t see the last boundary stone. He thought he should have seen it by now. The glow on the horizon didn’t seem any closer, in fact it looked to be receding as if it were being out blotted out by the dark.

He stumbled and nearly fell. There was the last boundary stone and there was a Raven.

“Corpse corpse”
“Corpse corpse”
“Corpse corpse”

The man stopped and looked at the Raven. The Raven looked back at him, eye to eye.

The man became aware of the dead around him and knew in fact he must be dead too. He could go on walking but would never get home. So instead he sat down next to the last boundary stone and waited.

The darkness gathered in.

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Ravens make a lot of different noises (listen here) – and can even learn to mimic words.

For a Halloween Raven-themed treat – both ominous and ghastly – try here.

Fostering hedgerow trees

John Beech – Land Management Adviser

Mature trees within a hedgerow network are an important feature in the countryside. This is where land managers across generations have allowed single hedgerow plants to grow to their potential, alongside hedgerow plants that are coppiced, laid, and managed to create a boundary. Hedgerow trees have no particular value in terms of land management, but have huge value for wildlife and for the landscape.

Re-laying a hedge - copyright NYMNPA.

Traditionally Elm, Ash and Oak trees were the dominant hedgerow tree species reaching heights of up to and over 30 metres tall, towering above the hedgerow corridors. Saplings that are allowed to grow higher than the surrounding hedge do not need to compete for light and therefore grow and spread their canopy high and wide up into the air. This provides a wonderful habitat kingdom for many species of wildlife, free from the clutch of ground based predators. Such trees act as key wildlife ‘stepping stones’ between woodland habitats and across a mixed landscape.

Large hedgerow tree near Low Askew - copyright NYMNPA.

The intensification of agriculture in the latter half of the 20th century including increasing field sizes resulted in the loss of thousands of miles of hedgerows along with their hedgerow trees. The outbreak of Dutch elm disease from the late 1960s onwards removed some 20 million elms from our countryside, mostly from hedgerows. It is therefore quite rare now to find a mature Elm tree within a hedgerow. Similarly Ash trees are now threatened by Chalara dieback.

In 1998 there were an estimated 1.8 million hedgerow trees in Britain (CPRE survey). Many of our over mature hedgerow trees today are beginning to die and slowly retrench. There is an adage that an Oak tree takes over 200 years to grow and then 200 years to die.

Planting hedgerow gaps between old hedgerow trees - copyright NYMNPA.

To check the loss of hedgerow trees we need to be planting new ones to replace the ones that are dying back. The 1998 survey revealed that only 1% of hedgerow trees were in the youngest age class (1-4 years old). Without successional planning there is a danger that these key features will be lost for good from the landscape and the disconnection between farmed land and semi natural woodland will become more marked than ever. It takes a leap of imagination but by planting now land managers will be leaving their mark on the landscape for their children.

Trees take time to grow. Native wildlife species use hedgerow trees but birds, bats and butterflies in particular favour mature hedgerow trees.

Hedgerow trees in the landscape - copyright NYMNPA.Tawny Owls take advantage of mature trees both as nesting sites and day roosts usually hiding close up against trunk. From a tree perch owls can see the movement of their potential prey on the ground below them. Bullfinches clamber amongst the branches searching for seeds, buds and insects. Treecreepers and Nuthatches use their Hedgerow trees in the landscape - copyright NYMNPA.acrobatic skills to forage for insects, nuts and berries and Woodpeckers drill away into the deadwood high in the canopy to make a home and feast on any tiny invertebrates in the wood. Butterflies such as Hairstreaks forage for honeydew from aphids and lay their eggs high up in the Oaks and Elms. Rich lichen communities also grow on the branches of old hedgerow trees.

In some of the older trees, holes and crevices provide ideal habitats for a variety of bat species. Around three quarters of British bat species are known to roost in trees. Bats use different parts of the tree for different reasons, depending on the time of year and temperature. In the summer bats use the higher canopy sites to have their young in warmer temperatures. In winter, they move deeper and lower into the tree to hibernate. Trees such as Oak, Beech and Ash are particularly suitable for bats, but any hedgerow tree has potential for a bat roost – especially if it has cavities in the trunk or branches, woodpecker holes, loose bark, cracks, splits and thick ivy. In Britain, all bat species and their roosts are legally protected by law.

Single hedgerow tree alongside an arable field - potential 'stepping stone' - copyright NYMNPA.

We’re working on enhancing wildlife corridors and connections through our habitat connectivity initiative, and as part of this we’re actively encouraging the planting of hedgerow trees where appropriate. With the loss of Elm and the threat to Ash, Oak is now the main species being planted in the North York Moors to become the hedgerow trees of the future. With good care and maintenance the trees should grow into vigorous specimens.

Mature hedgerow trees as a feature in the landscape - copyright John Beech, NYMNPA.

To foster hedgerow trees:

  • Select suitable saplings from within an existing hedgerow and add a tree tag to the top of it. This shows/reminds the person who cuts the hedge to leave this strong sapling to grow into a mature tree.
  • Alternatively, plant a hedgerow tree adjacent to an existing hedge to add variety and height. This has the added advantage of widening the hedgerow and enables useful wildlife buffer strips to develop along the hedge bottom. If there is an existing gap within a hedgerow that is wide enough to accommodate a hedgerow tree then plant a new tree there.
  • Try to avoid uniform planting and instead plant the new trees at irregular intervals along the hedge line. Planting two or three together may also be suitable for instance if a site is next to a field corner.
  • Plant trees with local provenance that will be used to the local conditions and be more likely to flourish.
  • It is best practice to add a tree guard or tube attached to a stake to protect a tree in its early years from stock, rabbits or deer. A mulch mat around the base of the tree helps to keep the weeds down. This will give the tree every chance to grow strong and straight.

Practical help and advice can be provided by the National Park Authority. Contact us.

The aesthetics of trees

Gallery

This gallery contains 41 photos.

Throughout the seasons, trees are like works of art in the landscape. Reason enough to value trees, not to mention they provide wood; clean and stabilise soil; produce oxygen and hold carbon dioxide; slow the flow of water; give shade and act … Continue reading

Seas of Green

Simon Hirst – River Esk Project Officer

New Zealand pigmyweed (Crassula helmsii) was introduced to Britain from Tasmania in 1911. By 1927 it was being sold as an “oxygenating plant” for garden ponds and aquariums by Perry’s Hardy Plant Farm in Enfield. The first recorded occurrence of pigmyweed in the wild was at Greensted Pond in Essex in 1956. It spread widely and rapidly due to the increasing availability of the plant at garden centres and aquatic nurseries.

This non-native invasive plant is now listed under Schedule 9 of the Wildlife and Countryside Act 1981. It is an offence to plant or otherwise cause this species to grow in the wild. The plant is now also banned from sale in the UK, which is a significant environmental step forward.

Crassula helmsii - copyright NYMNPA.

Crassula helmsii grows around the damp margins of ponds and in water up to three metres deep. It starts as a small light green tussock on sediment. The tussocks grow and spread rapidly to form a dense mat of vegetation. Severe oxygen depletion can occur below dense growths. The dense mat out-competes all other aquatic vegetation, eliminates native flora and creates a poorer ecosystem for invertebrates and fish.  The plant grows throughout the year and has no dormant period. Thankfully the pigmyweed does not produce viable seed in the UK but it can re-grow from small stem fragments.

New Zealand pigmyweed is very hard to eradicate when it has become well established. The plant is tolerant of shade for long periods, tolerant of frost and dessication, and it cannot easily be tackled by any existing method of environmental control.

Recently New Zealand pigmyweed was discovered growing in two ponds in Bilsdale which are both adjacent to the River Seph. The river is one of our key wildlife corridors. Working with our Apprentice team, we came up with a plan to carry out a programme of control which will hopefully result in eradication of this invasive plant.

One of the ponds in Bilsdale covered in Crassula helmsii - copyright NYMNPA.

One of the ponds in Bilsdale covered in Crassula helmsii - copyright NYMNPA.

We’ve covered the ponds with black plastic sheeting in order to prevent sunlight reaching the pigmyweed. This will prevent the plant photosynthesising, and should eventually kill it. The unsightly but purposeful plastic sheeting will need to be left on top of the ponds for six months, and we will be reviewing the situation next Spring!

Depriving the Crassula helmsii of light - copyright NYMNPA.

Depriving the Crassula helmsii of light - copyright NYMNPA.

Temporary black plastic over the top of one of the ponds - copyright NYMNPA.

Summer days

Kate Bailey – Conservation Graduate Trainee

Grasslands are important habitats in the North York Moors supporting a wide range of plants and wildlife. They’re habitats that have suffered severe declines all over England in the past decades. Therefore conserving, restoring, creating linked grassland habitats is one of the key focuses of our Habitat Connectivity initiative.

National Park Volunteers carry out regular tasks like scrub control in order to maintain and restore grassland sites. But volunteers are also essential when it comes to monitoring our grassland sites. Botanical monitoring is a key tool to ensure that the prescribed management is having a positive effect on the site, and the information collected through the annual monitoring process ensures management can be tailored to each site to help ensure each is in the best condition they can be or are at least moving in the right direction. Repeat annual monitoring means changes, good or bad, can be quickly identified.

Our Linking Landscapes Grassland Volunteers have been across the National Park this summer monitoring grassland habitats. We currently have ten enthusiastic volunteers who kindly give their botanical expertise and diligently undertake an annual botanical survey at their ‘adopted’ site/s.

Back in June the LLG Volunteers attended an informal workshop to work through the survey methodology and brush up on field identification skills before embarking on their own surveys for 2016. Copyright - NYMNPA.

This summer I’ve also been out surveying a number of grassland sites which hadn’t been surveyed previously; getting to visit some lovely spots whilst improving my botanical identification skills and collecting information.

Common spotted orchid in an old limestone quarry sites - nearly twice as tall as my clipboard! Copyright Kate Bailey, NYMNPA.

Both the volunteers and I have followed the same simple methodology for monitoring our site/s. A walking route is marked out on an aerial photograph for the surveyor to follow – the approximate ‘W’ shape ensures that a fair representation of the site is surveyed. The surveyor walks along the route stopping at regular intervals – ten stops is usually adequate. At each stop a square metre (quadrat) of vegetation is assessed and each species present is noted down – this is usually where the ID books and hand lens are invaluable.

The monitoring route for an area of species-rich grassland at Sutton Bank National Park Centre. Aerial photography copyright GeoPerspectives 2009 all rights reserved.

At the end of the ‘W’ shaped monitoring route, a survey sheet will look something like this.

One page of the grassland survey sheets - filled in - NYMNPA.

Because we’ve recorded which species are present in each quadrat at each of the ten stops we can work out the frequency of each of the species:

A species is rare (R) if it occurs in one or two stops out of ten;
It is occasional (O) if it occurs in three or four stops out of ten;
Frequent (F) species occur in five or more stops out of ten.

Common spotted orchid and Betony. Copyright NYMNPA.

Additional information is also recorded, including the amount of bare ground and height of the sward, the amount of scrub and bracken on site, and the presence of pernicious weeds (such as thistles, nettles and docks). Lots of photos are helpful, plus any sightings of notable wildlife!

All this information allows a site to be assessed and assigned one of the following categories:
Good quality species-rich grassland;
or
Good quality semi-improved or degraded grassland of high species-richness;
or
Semi-improved grassland of moderate species-richness;
or
Species-poor semi-improved grassland.

The National Park is keen to see an increase in the area of species-rich grassland. For the North York Moors that means the priority habitats lowland meadow and lowland calcareous grassland. By this regular monitoring we can get a clearer picture of the changing status of each site and use it to advise restoration methods. Altering the grazing regime, clearing bracken and scrub and/or sowing locally sourced wild flower seeds/spreading green hay can improve the quality and diversity of a grassland site with the ultimate objective of achieving and maintaining good quality species-rich grassland.

Ragged robin and Greater bird’s-foot-treofoil- indicators of the Lowland Meadow priority habitat. Copyright Kate Bailey, NYMNPA.

Common bird’s-foot-trefoil, Knapweed and Field scabious on a species-rich area of calcareous grassland. Copyright Kate Bailey, NYMNPA.

We’ll be out again next summer, doing it all again.