Landscape Journal - Summer 2017

Landscape The Journal of the Landscape Institute

Technical: Understanding the urban heat island effect / 58 Manchester’s urban realm / 08 Rat eradication in South Georgia / 37

Summer 2017

landscapeinstitute.org

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Editorial

By Ruth Slavid

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Why facts matter may be a truism that all our landscapes have, to some degree, been affected by mankind, but how we deal with the conflict between the ‘natural’ and human influence is an unending problem which needs careful consideration in every instance. Every decision that a landscape professional makes will have an impact, and it is not always clear whether that will be for the good – or even exactly what is meant by ‘good’.

Several pieces in this issue tackle those questions, especially in terms of native species and biodiversity.

On page 45, researchers at Sheffield University question the dictum that native plants are always the best for biodiversity and the wellbeing of pollinators.

They have carried out detailed investigations which show that the use of ‘near-natives’ in planned plantings may produce greater volumes of highquality pollen and nectar over a longer-period than will occur through a rigid adherence to the use of native plants.

And on page 53, an expert on a new disease of plane trees that threatens this country not only explains the problem but also argues that the threat comes less from the infectious agents than from our approach to management of woodland.

© 1 – Tom Lee

IT

Looking further afield, in fact to the other side of the world, our article on rat eradication in South Georgia (page 37), examines the principality’s ambitious and successful programme and questions how relevant it may be in countries with a wider range of fauna.

These projects all rely on hard facts and careful management, and there is a similarly painstaking approach in the article on page 58 that looks at just how much different paving materials contribute to the urban heat island effect. Although this article deals specifically with the Middle East, the approach would be appropriate anywhere in the world.

Most landscape professionals have good intentions, and want to do the best for their clients, their immediate environment and, ideally, the planet.

As the population grows and pressure on resources increases, they will have to make increasingly tough decisions.

It is great that so many professionals’ hearts are in the right place, but good intentions need to be backed up with knowledge rather than mere instinct.

We should all be grateful to the professionals who have put in the hard slog that not only solves an immediate problem but also enables many others to make the right decisions – even if sometimes those decisions are difficult. I hope this issue of the journal sheds some light and will encourage you to investigate further.

Landscape Summer 2017

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Landscape The Journal of the Landscape Institute

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Regulars 3

Technical

Editorial

Why facts matter

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Bigger picture

Antarctic life

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Update

walk round Manchester’s A urban realm Phil Griffin

64 Culture

LI conference in Manchester

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45

Planting for pollinators

Ben Gosling

66 On my mind

Branding the profession

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53

Plane truths about tree disease

The Landscape Institute provides a professional home for all landscape practitioners including landscape scientists, landscape planners, landscape architects, landscape managers and urban designers.

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The views expressed in this journal are those of the contributors and advertisers and not necessarily those of the Landscape Institute, Darkhorse or the Editorial Advisory Panel. While every effort has been made to check the accuracy and validity of the information given in this publication, neither the Institute nor the Publisher accept any responsibility for the subsequent use of this information, for any errors or omissions that it may contain, or for any misunderstandings arising from it.

Landscape is the official journal of the Landscape Institute, ISSN: 1742–2914 ©2017 Landscape Institute. Landscape is published four times a year by Darkhorse Design.

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eat gain and H paving selection

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Landscape Summer 2017

© 1 – Jack Brodie 2 – Lucio Montecchio 3 – Sebastien Miller

Publisher Darkhorse Design Ltd 21 Mann Island, Liverpool L3 1BP T 0151 649 9669 52-53 Russell Square, London WC1B 4HP T 0207 323 1931 darkhorsedesign.co.uk tim@darkhorsedesign.co.uk Editor Ruth Slavid landscape@darkhorsedesign.co.uk T 020 8265 3319 Editorial advisory panel Eleanor Trenfield, honorary editor CMLI David Buck AMLI Edwin Knighton CMLI Amanda McDermott AMLI Peter Sheard CMLI John Stuart Murray FLI Jo Watkins PPLI Jenifer White CMLI Landscape Institute president Merrick Denton-Thompson Landscape Institute CEO Daniel Cook To comment on any aspect of Landscape Institute communications please contact: Paul Lincoln, Executive Director: Marketing + Communications paull@landscapeinstitute.org

Features

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Rat and ruin A rat eradication programme in one of the world’s most remote environments is to be applauded – but how many lessons does it have for the rest of the planet?

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© 4 – John Pardey Architects 5 – The Decorators 6 – Ingo Arndt

Living in the landscape

In its first 10 years of existence, HAB has built some well-regarded housing in which landscape plays a crucial part. We look at the approach, at a number of key projects, and at the role that the developer’s landscape architect plays.

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Consult and collaborate If a landscape professional is involved in a project, is it a landscape project?

That is the conundrum posed by the work of The Decorators, but if the work is of value and significance, should we care?

Landscape The Journal of the Landscape Institute

Technical: Understanding the urban heat island effect / 58 Manchester’s urban realm / 08 Rat eradication in South Georgia / 37

Summer 2017

landscapeinstitute.org

A demonstration of the urban heat island effect (page 61)

© Sebastien Miller

Landscape Summer 2017

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Bigger Picture

By Ruth Slavid

Antarctic life

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h is photograph shows salps on a beach in the Antarctic.

They are officially described as planktonic tunicate. While they are both interesting and attractive, their presence in the Southern Ocean can be a sign that all is not well.

Populations of salps are increasing while that of krill is falling. And krill is the mainstay of all animal life in the Antarctic. Directly or indirectly, birds, seals and whales all depend on these small shrimp-like creatures. Have you ever wondered why so many penguins have pink-stained chests? That’s krill.

Salps, in contrast, have little nutritional value.

Krill is still abundant (there is a greater weight of krill than people in the world), but on the decline. The reasons include warming seas and the indiscriminate harvesting by factory ships. Krill is widely used in fish farming, for instance to ensure that salmon are pink, and also in human nutrition or as a source of protein or of omega-3 oils. Travel to the Antarctic and you will begin to realise just how worrying this is.

The salps pictured here are on the beach at Whalers’ Bay, Deception Island. The bay is within the island, created as the caldera of a volcano that is still active. Hence the water is warmed ‘naturally’ and the salps love it. Which is perhaps a valuable reminder that occasionally local climatic changes are not due to human activity, and that there are still forces shaping the landscape that are not the responsibility of landscape professionals.

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Š ppppenguin Landscape Summer 2017

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Update

By Phil Griffin

A walk round Manchester’s urban realm With the Landscape Institute’s annual conference due to take place in Manchester on 22–23 June (see more details on pages 64 and 65), it is timely to look at developments in the city’s public spaces.

1 – Looking towards Salford, a growing district © Tom Lee

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n the last Sunday of July 2016, a group of six visitors from Australia met at John Ryland’s Library on Deansgate in Manchester, with sketchbooks, pencils and inks to hand. They were early arrivals for the 7th International Urban Sketchers’ Symposium that convened in the city the following Wednesday. One of the sketchers, a 75-year-old man from Melbourne, had never left his country before. From the high Victorian neo-Gothic library they turned right 8

Landscape Summer 2017

into the 21st century glass canyons of the commercial retail and leisure district that owner Allied London had named Spinningfields. Minutes later they were marched back out by a security guard who told them that they couldn’t sketch in this area rattling with chain restaurants and themed bars, without written permission.

The sketchers – there were 500 of them by the middle of the week – had arrived from all over the world – from Buenos Aires, Mumbai, Cape Town

and Cape Cod – crowding the pavements with stools and boards, lingering with watercolours outside tiled Victorian pubs. They sketched the heck out of Manchester. Only once were they told that they needed permission. Planning, designing and maintaining public spaces in cities are responsible tasks for trained professionals. Keeping a grip on the public space is a challenge to us all.

Manchester city centre was a mess in 2016, though the sketchers didn’t

2 – Greengate Square is one of Salford’s new public spaces 3 – Development of New Islington started with high hopes, then ground to a halt with the 2008 financial crash. © Tom Lee

seem to mind. The latest extension to the tram system, called the 2nd City Crossing, churned up streets around the Town Hall. It opened at the end of February this year. The biggest impact has been on St Peter’s Square, a 20,000m2 levelled space incorporating two twin-platform tram stops.

Latz + Partner won the design competition in 2012. Sonja Hlawna led the project, which involved reordering and/ or removing a number of familiar and fiercely supported elements, not least the city’s Grade II* Cenotaph, the elegiac suite of Portland Stone structures designed by Edwin Lutyens in 1924.

Re-siting the Cenotaph required removing the Peace Garden and its two associated sculptures, Messenger of Peace (Barbara Pearson 1986) and Struggle for Peace and Freedom (Philip Jackson 1988). Into the mix went a part-time crèche, built largely for the benefit of Town Hall staff. Sonja fought drawn-out campaigns over Peace and the kindergarten.

Meanwhile, two new commercial buildings, by architects Glen Howells and SimpsonHaugh, now form the southern edge of the square, whilst the refurbished Central Library and Town

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Hall Extension contain it to the north.

Tram-lines bifurcate either side of the relocated St Peter’s Cross, elevated on a taller plinth and given greater prominence and visibility than before.

Road traffic has been removed from the square, and purple flowering Paulownias are about to hit their third surprising spring. Doubtless Latz + Partner and Arup, the engineers, needed all the client support they could get, but fair play to MCC for

commissioning on such an optimistic scale whilst dragging along the bottom of a muddy recession. The volume of Mancunian moans and gripes, which could even have filled a space as big as this, is drowned by a tide of civic appreciation. We like our tram, have adjusted to the baffling new road layouts, and soon forgot the turmoil.

Four Metro stops east of St Peter’s Square, on the line to Ashton, is New Islington. The 12-hectare Millennium

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Update

4 – Cotton Fields and New Islington 5 – The public realm in Cotton Fields is well considered © Tom Lee

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Village Initiative allegedly had a £250m budget. English Partnerships, along with MCC through its New East Manchester initiative, which involved the 2002 Commonwealth Games, amassed the pot. The lead developer was Urban Splash, to a masterplan by Will Alsop. Grant Associates was the public-realm consultant. Funding for this scheme, to replace a failed 1970s council estate with new-cut canal arms, a marina and sustainable water park and 1500 dwellings, was secured in 2002. The financial crash of 2008 scuppered the whole ambitious flotilla.

Grant Associates laid out Old Mill Street and Cotton Field, the marina and Water Park. The design standards, materials and vision of these elements were at levels not seen in the city since the Victorians. Tall, swooping CorTen steel streetlights form a guard of honour above the carriageways on Old Mill Street. Aquatic plants from the local canal system are the motifs of cast bronze roundels that form the planters for trees. In Cotton Field Park and New Islington Marina is a 10 Landscape Summer 2017

winding three metre wide boardwalk, with rising islands like stone fortresses, tall Scots pines, a beach and an island orchard. Little is maintained; much is trashed. Two of the expensively created canal arms are landfilled now, to make ground for more mundane but necessary housing. The current developer is Manchester Life, joint venture between MCC and Abu Dhabi United Group, owners of Manchester City FC, whose stadium is a short stroll along the Ashton Canal. I’m not a party to what Andrew Grant thinks of this outcome.

Cross the Rochdale canal by the newish perforated plate-steel footbridge (competition winning entry by Gollifer Langston Architects, with Michael Hadi Associates as engineer) onto Redhill Street and Ancoats Urban Village. Development here largely (though not entirely) missed out on the pre-’08 boom, but is now looking like one of the winners. Ancoats is ground zero in Cottonopolis, and its wasted mills and gridded streets finally win the attention and investment they

deserve. Public realm has a way to go yet, but signs are good around Hallé St Peter’s, the brick and stone Italianate church, complete with handsome campanile, now home to Hallé choirs and rehearsal rooms.

Next to St Peter’s is Cutting Room Square. Its design is a simple dropped space, overlooked by five vertical light boxes framed in patinated copper, displaying enlarged details of

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6 – In St Peter’s Square, St Peter’s Cross has a new, more elevated position 7 – New tram lines 8 – Cutting Room Square © Tom Lee

photographs of the Royal Mill cutting rooms in the dilapidated state they were found in the late 1980s. The photographs and the installation are by artist Dan Dubowitz who, as Ancoats’ artist in residence, created a number of interventions called Ancoats Peeps in 2010.

Cutting Room Square lacks attention just now, but there is plenty of development scheduled adjacent to it, including an extension to Halle St Peter’s, new housing, and an extension to the square itself. All of which bears good testimony to the treatment and quality of the space and the undeniable achievement of collaboration between designers and artist, under the management of Ancoats Urban Village, the public-private agency established by MCC. From Cutting Room Square you might walk on to Great Ancoats Street and head north towards NOMA. This is the name given to the former Co-op estate that clusters around the footings of the 1960s CIS tower and the new HQ building, No 1 Angel Square. It hasn’t all been plain sailing for the Co‑op in recent times but, as well as the new headquarters building (3DReid architects) and a public-realm master plan by Mecanoo, NOMA boasts Sadler’s Yard (Planit-IE 2015).

If you like hidden-away, secluded bits of cities, this is for you. Not many people find Sadler’s Yard, which is named in a historical reference to James Sadler who made balloon ascents from around here in the early 1800s. Balloon Street is close by.

Essentially, the rectangular space fills in Redfern Street, which previously circled a couple of the Co-op buildings, behind the original Co-op Bank, and the 1960s complex of New Century Hall and Tower. The square has a referential materials palette, raised levels to focus on performances and bespoke lighting towers. At one end, the Yard terminates in quite a tall stair.

There’s a timber-clad single-storey pub called Pilcrow, hand built by volunteer craftsmen and trainees. It is a shame that it doesn’t more resemble the neighbouring Miesian pavilion of New Century House, looking instead

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Landscape Summer 2017 11

Update

9 – Cathedral Gardens is one of the spaces created after the 1996 bomb 10 – Sadlier’s Yard is a somewhat hidden new space. © Tom Lee

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rather like an extruded garden shed.

Altogether, this is a welcome addition for hundreds of Co-op office workers, but no single aspect is as pleasing as the generations of fine Co-op buildings that surround it.

Should you have found it, Sadler’s Yard is just a few steps up Corporation Street from Cathedral Gardens, one of three public spaces created in the Simpson Architects – EDAW (now SimpsonHaugh – AECOM) masterplan, following the 1996 IRA bomb. Simpson placed his Urbis building (now the National Museum of Football) at the street edge of a large Blitz gap-site. This opened up the space behind for Cathedral Gardens (BDP Landscape 2002). The undulating green swathe and unreliable cascading water-margin has been popular ever since, largely with teenage Goths, Emos and Moshers. Quite why this should be is difficult to explain, but Simpson always claims his masterplan was intended to help link the north and south of the city. It certainly does that 12 Landscape Summer 2017

for a large but specialist sector of youth.

In June 2016, the Urbis building hosted a seminar commemorating the 1996 bomb. Ian Simpson was one of the speakers, alongside Jason Prior and James Chapman from the EDAW team and the Task Force, and New York landscape architect Martha Schwartz.

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Clearly, Prior gained much from his experience of working with Howard Bernstein (now Sir Howard Bernstein, and shortly to retire from his role as CEO of Manchester City Council) and the task force set up to repair the city after the bomb. He has since exported his skills to other parts of the world.

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Update

11 – Martha Schwartz is unhappy about the way that Exchange Square has fared.

12 – Piccadilly Gardens © Tom Lee

The EDAW-led scheme for the renewal of Piccadilly Gardens featured in an exhibition of public spaces in New York’s Museum of Modern Art. It was a pity, on the day, that Prior seemed oblivious to the public acrimony the scheme has engendered – for its failed water feature, repeated re-seeding, poor performance – across a period when it has, in a number of respects, become the rather higher maintenance space that its success has engendered.

In particular, one significant element of the scheme, a curving exposed shuttered concrete wall designed by celebrated Japanese architect Tadao Ando, and brokered by James Chapman, is to be demolished, ahead of wholesale refurbishment.

Martha Schwartz, on the other hand, is acutely aware of the performance of her competition-winning design for Exchange Square, a road-fill scheme to redirect traffic from the area of the Corn Exchange and New Cathedral Street. She thinks it is so abused as to be unrecognisable as the scheme originally commissioned. She could barely bear to look at it on the day of

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the seminar. She had harsh things to say about MCC as her client. Her experience was painful, and reflects some of the issues that landscape architects face now. Their schemes are often adapted without reference, hopelessly underfunded in maintenance and completely redirected by subsequent ownership,

private and public.

You might, at this stage in your tour, want to divert to another city entirely. Salford is a hundred metres away, just over the new River Irwell footbridge. Walk, drive or cycle west along Chapel Street and see remarkable change. Manchester’s poor neighbour is, at last, cashing in on lower land

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Update

values north of the Irwell, and the residential sector is booming. Chapel Street itself is being carefully and thoughtfully treated, and the blackened gaps of street-line decay are gradually being filled. Up and round the handsome Crescent, as far as the University, the street is being flossed.

University residential halls are woven into Peel Park, the space between the museum and the River Irwell that, when it opened in 1846, kicked off the whole public park thing.

Back to Exchange Square and hop on the tram to MediaCity UK. Here you might find, if you look hard enough, another celebrated garden. Tucked away by the tram stop is the Blue Peter Garden, complete with Petra’s memorial.

This was transplanted here, along with two thousand BBC employees, in 2011.

The huge and valuable development is by Peel Holdings. The organisation is not keen on photographers with tripods, and without permission, but no sketchers have been evicted so far.

The tram stop fits into the wide piazza well. The landscape is nothing great, but the circular walk from here, across the two rather fine footbridges, via Imperial War Museum North and the Lowry arts complex, is exhilarating on a fine day. The skies here are as big as they get, so close to the Manchester metropolis.

The city recently voted for a new mayor for the newly constituted Greater Manchester authority. The officers and members in Manchester Town Hall in Albert Square might not be comfortable with it, but as Sir Howard packs to enjoy his retirement after twenty remarkable years as the city’s CEO, Manchester is changing shape. For the second time in a century, it is heading west, along the Ship Canal. Its banks will not be lined with industry this time, but with huge residential development and, hopefully, public realm to the very highest standard, free to access by passing sketchers.

Phil Griffin is a freelance writer and curator with a special interest in architecture and urban issues.

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13, 14, 15 – Media City Salford, home of the BBC, is a new environment that includes the Blue Peter Garden and two fine footbridges. © Tom Lee

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Landscape Summer 2017 17

Living in the landscape

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Feature

In its first 10 years of existence, HAB has built some well-regarded housing in which landscape plays a crucial part. We look at the approach, at a number of key projects, and at the role that the developer’s landscape architect plays.

BY RUTH SLAVID

Landscape Summer 2017 19

Feature

1 – At Lovedon Fields, the bars across the tops of the gates provide bridges for wildlife.

do we live where we do? And what makes us happy about where we live?

These are the questions that engage HAB housing, the organisation started 10 years ago under the auspices of TV’s Kevin McCloud and which has delivered a relatively small number of well-regarded projects in both the public and private sectors.

WHY

HAB stands for ‘happiness architecture beauty’ but from the beginning there has also been an emphasis on landscape, and that is only set to grow. The practice has always worked with talented landscape practices but for the past three years it has also employed an in-house landscape architect, Catherine Haigh. In her time in private practice, Catherine worked for an architect and also in a multi-disciplinary practice. ‘It enabled me to see where the bits were missing in terms of making things happen,’ she said.

Making things happen is what HAB does with a mixed portfolio that is difficult to define but somehow easy to grasp. The very first project, The Triangle, in Swindon, still the most highprofile, was entirely publicly funded, partly because working with a housing association was the only source of funding the nascent company had access to.

It developed a site that several previous developers had dismissed as impossible, and this set a pattern for future developments. Too small to compete directly with larger developers, HAB looks for or becomes aware of parcels of land in the southwest, its chosen patch, that are seen as difficult and finds solutions.

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© John Pardey Architects 2 – Applewood in Stroud melds with its surroundings © Tim Soar 3 – The pump at The Triangle is at the centre of a communal growing area © Paul Miller

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Isabel Allen, who has been design director of HAB from the beginning, said, ‘We are always interested in the vast majority of housing, much of which was previously unloved and uncatered for.’ The practice is committed to One Planet Living (the notion that we should not consume more resources than our planet can provide sustainably), and is trying to make this applicable to as many people’s homes as possible – hence its tendency to build on the edges of towns, rather than providing city-centre glamour or rural hideaways.

And in those places, landscape has a vital role to play. Isabel says, ‘Housing is not meant to be the soloist in the orchestra. If you want some richness it is easier to have that in the landscape.’ As well as creating spaces within the developments that can have social as well as recreational function (typically there will be small private gardens and also communal space), the practice likes to ‘borrow’ from the surrounding landscape. ‘A lot of it is about communication,’ Isabel said. ‘The badgers are already there, the hills are there. What we do is a prompt. It is about wrapping up a story and engaging people.’

The practice has worked with an impressive array of landscape architects, but is always looking for more. Isabel has her finger on the pulse of suitable architects – she used to edit The Architects’ Journal – but, she says, ‘one of the clear briefs to Catherine was to research the landscape architects out there.

If, for instance, SuDS are very important in a scheme, she should know who to go to.’

The Triangle Landscape architect Studio Engleback Architect Glenn Howells Architects Engineer Curtins Consulting Photo © Paul Miller

HAB’s first project, The Triangle in Swindon, was delivered by Haboakus, a joint venture between HAB Housing and GreenSquare Group. The 42-home development on a sustainable brownfield infill site sought to create a contemporary interpretation of Swindon’s mid-Victorian railway cottages – flexible, affordable and efficient to build and run.

The scheme consists of two and two-and- a-half storey terraces containing two-, three-, and fourbedroom homes around a central village green.

The east and west terraces are both terminated by three-storey corner blocks, each containing three apartments, providing focal points as you enter and leave the site.

The architectural expression is deliberately low-key, deriving its character from proportions, carefullydefined details and high-quality execution; a well-ordered backdrop which allows the extensive landscape and greenery to define the character of the site. Gabion walls to the front of the dwellings minimize the visual impact of car parking, conceal meter cupboards, recycling and bins and provide nooks and crannies to encourage wildlife. Details like these were considered carefully – the gabions

were too low to sit on, to maintain some privacy, but the right height to perch a cup of tea. In addition to private rear gardens, the scheme provides a range of public and semi-public spaces to encourage recreational use, hobby gardening and strong social interaction between neighbours. The central green includes a wet meadow, which forms part of the sustainable drainage strategy, and a wildlife garden as well as an area for community activities and informal children’s play.

The landscape strategy throughout the scheme maximizes the opportunities for food production with kitchen gardens, vegetable patches, allotments, planters, fruit trees and currant bushes.

Completed in 2011, the project won a raft awards.

Studio Engleback won a SWIG (Sustainable Water Industry Group) award for the project’s approach to sustainable drainage and the Communications and Presentation category of the Landscape Institute Awards for Grow2Eat, a gardening guide/ cookbook detailing all the edible plants at the Triangle and giving advice on gardening, harvesting and cooking.

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Feature

Applewood, Stroud Applewood is a community of 78 sustainable homes ranging from one-bedroom apartments to four-bedroom houses on the site of a derelict Victorian hospital in Cashes Green on the outskirts of Stroud. The development is 50% market housing with 50% designated as affordable for local people.

HAB was appointed following an open competition to find a development partner that would deliver well-designed and sustainable schemes while also drawing on the site’s history and landscape.

Public consultation revealed that the local community was particularly attached to two existing buildings. The new homes echo the textures and colours of these and other buildings in the area.

Streets have been designed as social spaces with high-quality materials and careful landscape design creating ‘natural’ traffic calming and a pleasant environment for pedestrians and cyclists.

Dialogue with local residents informed the design of a sustainable drainage system which not only serves the project itself but also alleviates preexisting flooding issues in the wider area.

The project includes a variety of green spaces which draw on and enhance the site’s environmental qualities and are available for use by residents and the wider community. These include: a ‘pocket orchard’; a natural wildlife corridor which runs through the scheme and incorporates an existing badger sett; a landscaped public square and public allotments that are being bought back into use after decades of disuse.

Landscape architect Studio Engleback Design architect: DSDHA Executive architect: Quattro Engineer Curtins Consulting Photo © Tim Soar

Gabion basket retaining walls provide habitats for wildlife. A new allotment building incorporates a purpose-built bat roof and there are bird and bat boxes throughout the site. This modest building has become an important social hub.

The project, which was completed in 2015, merges into the surrounding area, becoming part of a wider neighbourhood.

Avon Wildlife Trust Cabin This tiny project provides a semi-seasonal shelter for volunteers, school classes and visitors to a new nature reserve in the Avon Gorge.

The Trust was clear that it wanted the building to celebrate the view of the reserve and to enjoy good natural light, but stipulated that there should be no visible glazing – there have been issues with vandalism on the site. Crucially, the project had to be delivered for a total cost of £30,000.

Hugh Strange’s solution was to take a simple, ‘off the shelf’ agricultural building and to extend it and adapt it to meet the requirements of the brief.

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The building sits on an existing concrete ground slab in order to minimise disruption to the site and to reduce cost. Native herbs and flowering perennials have been planted into cracks and trenches in the concrete to attract insects and make the slab a more attractive base for visitors to congregate and linger.

The project was built in 2015 and was the joint winner of the 2015 AJ Small Projects Award.

Architect Hugh Strange Architects Photo © David Grandorge

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The Acre, Cumnor Hill, Oxford Landscape architect Robert Bray Associates Architect John Pardey Architects Engineer AKS Ward Photo © John Pardey Architects

The Acre is a development of five detached family houses in Cumnor Hill, a suburb of Oxford.

It is HAB Housing’s first foray into high-end private housing.

The 0.49 hectare site was previously an area of coniferous plantation woodland within the private garden of Larkbeare, an Arts & Crafts style house designed by the architect Clough Williams-Ellis.

The new houses are arranged as a cluster around a common court, within the sloping site.

Each house is designed as an L-shape – a twostorey house with a single-storey garage wing – enclosing a protected, private garden space.

Whilst modest in size, the gardens have been designed as an integral part of the architecture, with an emphasis on functionality and aesthetics.

Living rooms spill out onto outdoor seating areas positioned to take advantage of the particular orientation of each house. Some houses have external stairs to large first-floor terraces; others have green roofs above the garage – the result is a multi-layered landscape that echoes the terraces of the sloping site.

Robert Bray Associates has turned the challenge of keeping water run-off to pre-development levels into an opportunity rather than an engineering problem. Surface-water drainage has been carefully designed to complement and enhance the development’s character, with runoff managed within two catchment areas containing interconnected SuDS elements within the private gardens and shared space. Rainwater is collected from roofs and areas of hard surfacing, and conveyed via a series of pools, channels and rain gardens into basins and gravel storage layers, and at the end of the train into an existing ditch.

The project is currently on site with completion scheduled for June 2017.

Lovedon Fields Landscape architect BD Landscape Architect Design architect: John Pardey Architects Executive architect: BBA Engineer Clarkebond Photo © HAB Housing

Lovedon Fields is a 50-home residential scheme which forms a new edge to the village of Kings Worthy in Hampshire.

From a single point of access off Lovedon Lane the houses cluster round the upper part of the site around a triangular open space – the Grove. An avenue, with houses on both sides, runs along the lower contours and re-defines the village edge against a new 4.6 ha park.

The new park is a significant extension to Eversley Park, and has been designed as a low key, ecological landscape with allotments, a bike track, running circuit, natural play area, wildflower grassland, footpaths and enhanced boundary plantings.

The project as a whole has been designed with local wildlife in mind. New habitats and movement corridors are being created, at varying scales within the park and housing areas; for birds, slow worms, bats, hedgehogs, invertebrates and swallows. Bat boxes, bird boxes and bee bricks are incorporated into the houses’ brick walls.

The project is currently on site and with the houses scheduled for completion in September 2017 and the park due to be handed over in 2018.

As part of the park works, HAB is trialing the establishment of four hectares of wildflower meadow without the use of herbicides or chemicals.

Landscape Summer 2017 25

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Elderberry Walk, Southmead, Bristol The project, which was won in a Bristol City Council competition, has been designed around a central Green Lane – a 20m wide route for people, wildlife, drainage and play which provides a strong social and focal identity for the development and links the surrounding residential area to local bus routes and to the park which lies to the north of the site.

Sustainable drainage has been designed as part of the streetscape, using a combination of permeable paving, rain gardens, swales and basins to convey and hold runoff.

Looking ahead If it is hard to see where HAB is going next, that is only because it grasps the opportunities as they arise, rather than having a rigid road map. It will continue to concentrate on the southwest, and primarily on the edges of towns. Its commitment to sustainability in all forms and to creating decent

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Housing is designed to be efficient and economical to build and run, with an emphasis on simple two-storey terraced forms. Houses are arranged in courtyards offering a range of different conditions: private rear gardens or more modest private gardens opening onto a shared garden square. Irregular geometry at the corners of the courtyards offers opportunities to play with more unusual forms.

Landscape architect Design: Clifton Emery Design Detailed design: Churchman Landscape Architects Architect Allford Hall Monaghan Morris Engineer Arup Image © AHMM

Thirty per cent of the homes will be affordable housing for United Communities – both for rent and shared ownership, whilst 25% will be for a new form of private rent. Construction will start this year with completion in 2019.

places to live is indisputable. And it will continue to do that by creating and borrowing landscape.

Being HAB’s landscape architect is an exciting job, and one that will actually affect more people’s lives for the good than may be the case for many practitioners embedded in design practices.

Inspiring Sustainable Spaces

Project: Fridewide Square, Oxford Client: Oxfordshire County Council Contractor: Skanska Designer: The Urbanists Planning & Design

Contact us for more information 7 01708 867237 enquiries@ceed.ltd.uk www.ced.ltd.uk

Landscape Summer 2017 27

28 Landscape Summer 2016 2017

Feature

Consult and collaborate If a landscape practitioner is involved in a project, is it a landscape project? That is the conundrum posed by the work of The Decorators, but if the work is of value and significance, should we care?

BY RUTH SLAVID

Landscape Summer 2016 29

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2 – The pop-up restaurant in Ridley Road, Dalston sourced its produce from the adjoining market.

WHEN

Kinnear Landscape Architects won the LI’s President’s Award in 2015 for its project ‘Brentford High Street – making the connection’ there was delight that a relatively quiet project, by a quiet practitioner, had taken the top prize. Lynn Kinnear always gave credit to the collaborators with whom she worked, although in the nature of such things they sank somewhat into the background.

3, 4 – The temporary garden at Alexandra Palace is put away each winter and reinstalled in the spring © The Decorators

One of these collaborators was a young practice called The Decorators that was involved particularly in the vital public consultation side of the project.

And when I say ‘practice’ there is a deliberate ambiguity, because it is hard to define what kind of practice it is. One of the four founders is however a landscape architect and she is in no doubt that what she is doing is landscape architecture.

Suzanne O’Connell who, in addition to her work in practice also teaches at Greenwich University, said, ‘Over the years I have become more confident that what this is, is landscape. The thinking can be the same.’ ‘This’ is a body of work that centres on consultation and on changing the ways that people think about and experience a place.

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The physical outcomes may be modest but, as one of her colleagues Carolina Calcedo said, ‘the value is not necessarily in what you see but in the building of connections’ Carolina has perhaps the most unusual background of the foursome that make up a practice that operates in the world of the built environment. Her degree is in psychology, although she switched to it from a start in studying engineering. She discovered, she says, that what interested her most about spaces was the way in which people related to them rather than the physical infrastructure. She has, says Suzanne, ‘a really good eye’.

Suzanne and Carolina met each other and the other two collaborators, architect Mariana Pestana and interior designer Xavi Llarch Font on a postgraduate course run at Central St Martin’s in London called ‘creative practice for narrative environments’. It was, said Suzanne, ‘very collaborative’, looking at a range of organisations, at public space, cultural institutions and commercial buildings.

The four started working together in 2010, in a way that was entirely fluid and flexible, says Suzanne.

After a while, she says, ‘we realised that we needed to sort ourselves out in terms of getting work’.

They now have an office, although only three of them are there. Mariana Pestana is working as a curator at the Victoria and Albert Museum, although the others insist that she is still very much part of the team.

Their first real project was in Ridley Road in Dalston, east London. An architect called Zoe Chan (her practice is Atelier Chan Chan) owned the site in the busy market and asked them to come up with an idea. They carried out a lot of research and in the end settled on a temporary restaurant as a way of engaging with the area and the market.

Local chefs cooked meals using local produce only, and lunchers received a discount if they paid in the form of produce from a shopping list, bought in the market.

The project was short-lived (as was always the intention) but it garnered a lot of publicity.

The physical input was not enormous, with most of the effort going into research and organisation.

And into raising money – the team brought in funding from United House. ‘We just said we would make it happen,’ Suzanne said. ‘We sent out a lot of fliers and sponsorship letters’.

This is very much the way that The Decorators works. Another effect of Ridley Road was that they put themselves ‘on the map’, being put on the ‘special assistant team’ at the GLA.

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Even on a seemingly more conventional project, the practice was appointed because of its approach to consultation. This was the case in Hayes, Middlesex, where the practice was invited to look at public space and came up with the idea of playing ‘sounds of Hayes’ from a 5m high ‘clock tower’. This references the historic importance of Hayes as the former home of record producer EMI. The idea is that a series of chimes, which will change every six months, will be based on the best-loved of EMI’s tunes.

The Decorators organised a radio programme in which residents were asked to choose their favourite tunes from the EMI archive. These have then been made into the chimes.

On Streatham High Road in south London the team worked with the local Business Improvement District to develop what they describe as ‘civic stops’ – providing seating and plants for three locations.

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Also plant-based was the work at Alexandra Palace in north London, where the team developed a mobile garden in containers that can be put away each winter and brought out again in the spring.

Far more ambitious in scale was a project at Heyford Park near Bicester. There are about 300 homes on the former RAF base, with virtually no infrastructure but a strong community.

Now developers are planning another 1200 homes and invited The Decorators to work with developers and local authorities and the local community to see how the best of what exists in terms of atmosphere can be preserved, and integrated with the lives of the new residents.

‘We spent six or seven months doing one to one interviews with about 30 residents, ‘Suzanne said, ‘and set up co-design workshops’. The results included the adoption of a temporary public communal space as a ‘show village hall,’ analogous to the show homes that developers build.

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4 – At Heyford Park, an astronomy evening to look at Mars celebrated the locals’ interests 5 – The Tasting Station was set up on the former runway at Heyford Park 6 – The Decorators designed the furniture for The Brasserie at Heyford Park 7 – A range of events brought animation to North Limehouse Basin 8 – New seating at North Limehouse Basin © The Decorators

Activities included catering and a performance stage, but also more unusual events. The Decorators discovered that there were several keen star-gazers and set up astronomy evenings, and also that there was an interest in archery.

In physical terms, the team produced some chairs and a temporary stage, but the impact was far greater in terms of making the existing community feel that it was not neglected. But there were also some hard lessons for The Decorators.

‘We had quite a fraught time working with a private developer,’ Suzanne said. ‘It raised a lot of concerns. We have been thinking since then about having a code of conduct – in future we would have a much stronger contract and definition of how we operate.’

of bringing people together. At North Limehouse Basin the quartet were commissioned by the Canal and River Trust to look at the fast-changing area and to address complaints about anti-social behaviour. The result was the Limehouse Social, a series of community events for which the team designed some planters and seating. A market was also set up, which is continuing to do really well, although some of the other activities have, unfortunately, been discontinued. Now the team are looking at ways in which the animation that the market brings on Saturdays can be continued into the week.

All this sounds really simple, but took around six months to get in place. And the team is also working, in a continuing collaboration with Sue Ball of public arts consultancy MAAP, on a spare piece of land to find new community uses for it.

It seems that food is important to The Decorators, and why not? It is after all one of the simplest ways

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It seems that the potential conflict between existing and new communities is a rich seam of work for The Decorators. At Hackney Circle in Dalston Square the team is working with developer Barrett which is building new homes and worried about leaving existing, older residents behind. The Decorators undertook a study, talking to residents of two sheltered housing schemes and finding what they wanted. Ironically or not, they then held a meeting at a ‘hipster’ café, discussing what this older age group wanted or didn’t like.

While the first outcome for The Decorators was to design a set of chair covers to make the seating more comfortable, this then expanded to a membership scheme for the over-60s, funded by a series of local businesses, that gave them access to facilities and also to a range of activities in a summer festival. For a developer facing possible accusations of gentrification, this kind of work is invaluable.

For The Decorators however, there is an obvious problem, in getting clients to acknowledge the value of their work. If the physical outcomes verge on the trivial, the intangibles are much greater –

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and require a lot of effort. But, says Suzanne, the team members are having to find ways to persuade clients to pay a fair price for these intangibles.

The quartet have been attending a business course for a year and a half and are obviously committed to making their business financially sustainable.

But this will be on their own terms. ‘We have been having reflections on our process,’ Suzanne said.

‘We have been asking if some of the work is responsible if it doesn’t go anywhere afterwards – it has to be part of a longer term journey for the place.’

Reflecting is something the team do a lot. ‘We used to spend hours talking and criticising projects,’ Suzanne said. ‘It wasn’t sustainable – we are probably a bit quicker now.’ But, she added, ‘we always slip into each other’s pockets in terms of practice.’

Is this landscape? One could probably argue for days about it. But it most definitely is a way of working that is informed by the sensitivities, knowledge and perspective of a landscape architect as well as by the other disciplines. And, crucially, for those whose lives have become richer.

9 – A range of events were designed to appeal to older residents at Hackney Circle © The Decorators

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Landscape Summer 2017 35

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36 Landscape Summer 2017

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Feature

Rat and ruin A rat eradication programme in one of the world’s most remote environments is to be applauded – but how many lessons does it have for the rest of the planet?

BY RUTH SLAVID

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Landscape Summer 2017 37

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i sland of South Georgia in the Antarctic has carried out the most ambitious rat eradication programme of any island anywhere in the world. And it has done it in a race against time – before the glaciers that divide the island into manageable zones retreat so far that the island becomes one happy playground for invading species.

THE

The results so far have been stunning – rats have gone as far as can be told and colonies of the South Georgia pipit, the world’s most southerly songbird, are reappearing. Previously the bird had become restricted to outlying islands.

It is a success in its own terms, having surpassed earlier successes in New Zealand, and inspiring that country to even greater efforts. The island has also got rid of reindeer, an ill-considered introduction, and has strict biosecurity measures.

The tale is a fascinating one, but does raise the question of how often it can be emulated and whether it should be. South Georgia is a special place. Does it have lessons for the rest of the world?

To understand just how unusual South Georgia is, it is worth recalling that last December the astronaut Buzz Aldrin was evacuated from the South Pole after falling ill on a tourist trip, albeit one that few of us could afford. Tourists can, in the summer season, fly to the South Pole. But nobody has ever flown to South Georgia. The island is too rocky for an airstrip, and too far from anywhere else for helicopters to reach it.

Typically a cruise ship or equivalent takes two and a half days to cover the 1,550 km from the Falkland Islands to South Georgia. Any evacuations, for medical or other reasons, have to be by sea. There are no harbours, with all but the smallest ships having to moor offshore. The population is tiny, with between 20 and 25 people living there in the summer, fewer in the winter. They comprise Government officers (South Georgia is a British Overseas Territory), members of the British Antarctic Survey (BAS), and members of the South Georgia Heritage Trust, which runs the excellent museum on the island – and also ran the rat eradication programme.

1 – Rat and bait on South Georgia 2 – The South Georgia pipit is the world’s most southerly songbird. © Brian Gratwicke from DC, USA South Georgia Pipit, CC BY 2.0, https:// commons.wikimedia.org/w/index. php?curid=24736657 3 – Helicopters delivered bait throughout the island’s difficult terrain. © Ingo Arndt

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But South Georgia has a far more populous history.

In the first half of the twentieth century, it had several successful whaling stations, with the last one closing in 1965. Nobody then was worrying about environmental issues, and invading plants came in as well as rats.

Obviously nobody likes rats, but eliminating them in South Georgia was particularly important because of the island’s fragile ecology. Plants grow very slowly in the harsh climate, which means that invasive species may take a long time to establish, and can then be devastating. There is abundant animal life, but that is in terms of numbers rather than variety. The beaches in summer are covered in fur seals and elephant seals, and the king penguins, the dominant species, can be numbered in hundreds of thousands on the most ‘popular’ beaches. There are no land predators, which is why the effect of rats was so devastating. The South Georgia pipit had no skills for evading rats.

Tony Martin, professor of animal conservation at the University of Dundee, had worked on the British Antarctic Survey base on Bird Island, off South Georgia where 20 years ago it was discovered that the population of albatrosses was ‘going through the floor’ for a variety of reasons. When he travelled to the mainland of South Georgia he was struck by the ‘night and day’ difference in the population of South Georgia pipits, a difference that was down to the presence of rats.

The decision by the South Georgia Heritage Trust to eradicate the rats was, Martin said, ‘a completely barking mad idea from the beginning’. Prior to this, its main responsibility had been running the island’s museum – a wonderfully curated resource, but a small one. ‘It was fundraising for signage around the museum,’ Martin said. Then it undertook this massively ambitious project.

What does it matter what Martin thought? A lot, in fact, because in 2009 he received a call from the trust and jacked in his job with BAS in order to lead the project. The South Georgia Heritage Trust had set about raising the £7 million that was needed to carry out the work. This was done in three stages each of which was self-contained because of the presence of glaciers separating the areas.

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But it was a pretty good bet that this would not be a problem because South Georgia has no native mammals, reptiles or amphibians. And, said Martin, ‘seals won’t touch the pellets’. Birds were therefore the only potential collateral victims and the first phase of work, if it had gone horribly wrong, would ‘only’ have eliminated 10 per cent of the birds on the island – and it was reckoned they could have recovered.

The logistics were difficult for all stages of the work, not only because of the terrain but also the weather.

One of the helicopters had its rotors bent out of shape in a ferocious storm despite being lashed down against the wind. Sophisticated GPS systems were used to ensure that the poison reached all the correct places.

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This was covering a far larger area than had been done previously, either by New Zealand on Campbell Island, or by the Australians on Macquarie Island.

South Georgia has a land area of 3,900 square kilometres, and nearly all of those are mountainous.

Apart from at the ‘capital’ Grytviken, where there is a track stretching a couple of kilometres, there are no roads. And the eradication programme had to get rid of all the rats – getting rid of a lot would not be enough. The island had to be rat free.

And the rats have gone. Not only have the rat trails in the snow disappeared, and the South Georgia pipits reappeared, but a variety of telltales put out to identify the presence of rats have come up negative. And the South Georgia Heritage Trust has invested in some cute dogs to sniff out rats!

‘Around the world all previous large-scale eradications had been carried out by governments,’ Martin said. ‘But the South Georgia government didn’t want to do it. So the South Georgia Heritage Trust said that they would do it. My job was to put at least one pellet in front of every rodent in South Georgia. How you do it is more complicated.

Doing it by hand is out of the question.’

The trust bought three helicopters (which were delivered by sea) and equipped them with buckets slung beneath them to contain the bait, an anticoagulant poison called Brodifacoum, which was coloured a bluish green since it had been determined that that was the colour least attractive to birds.

The reason for starting with a fairly small area was, said Martin, because, ‘as well as killing all the bad guys, you have to ensure that the mortality of nontarget species is sustainable.’ In other words, had the first part of the trial led to unsustainable mortality in birds or seals, it could have been abandoned.

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4 – Dogs are used to search for traces of rats post-eradication 5 – Tony Martin with one of the helicopters © South Georgia Heritage Trust

People returning from elsewhere on the island have to clean their clothes in the biosecurity area.

And it is not just the smallest invaders that are unwelcome. In the early twentieth century, Norwegian whalers introduced reindeer to the island, as a potential source of meat. They took a long time to establish, but once they did so, their numbers expanded. They became significant enough that there is now a reindeer on the crest of South Georgia. But that is the only place that you will find them. They were affecting the ecology of the plants, and so the decision was made a few years ago to eliminate them – largely by shooting.

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6 – The ‘village green’ outside the BAS headquarters is out of bounds to people because it harbours invasive species of plants – the fur seals take no notice © ppppenguin 7 – The colour of the bait was chosen to be as unattractive as possible to birds © South Georgia Heritage Trust 8 – Bait store, prior to distribution © Tony Martin

Rats are not the only possible invaders. Because vegetation grows slowly, and because temperatures are rising, there is concern that invasive plants could edge out some of the natives. An area of ground near King Edward Point, adjacent to Gritvyken, has been designated a no-go zone to prevent the spread of seeds from invaders. Visitors to the area are not allowed to put any bags down on the ground in case they carry seeds.

The story of South Georgia’s wildlife and in particular of the elimination of the rats is a fascinating one. It may not be over. There has been one definite sighting of a rat which, says Martin, almost certainly came off a ship. While large ships do not pose a hazard, because they cannot dock directly, there is a risk from visiting yachts. And, in particular, if a fishing vessels is ever wrecked on the island then the proverbial rats leaving a sinking ship could pose a very real risk.

When cruise ships arrive, all visitors have to go through Virkon disinfectant baths before disembarking onto inflatable boats. And clothes and bags are checked and vacuumed to eliminate seeds. Food coming into the island goes through a strict biosecurity regime to avoid the accidental introduction of bugs. The skins are stripped off onions, and leeks and broccoli are banned because they provide too many hiding places. This may sound extreme but earwigs, for example, have proved tenacious invaders on the Falkland Islands.

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Martin and others are concerned that, without even more stringent ongoing measures, the rats can, and indeed will, return. And if this is the case on South Georgia, what price eradication on other, more populous islands? There are many other questions as well. In the case of South Georgia there is an argument that its ecosystem is so special that visitors should not be allowed at all. And it is easy to imagine that, if populations of fur seals continue to recover and therefore tour operators find it ever harder to access the beaches (male fur seals are horribly aggressive) there could even be an argument for a cull. The tour operators work very closely at present with conservationists, but their business in the end is landing tourists.

Martin admits that he respects and even likes rats.

In the case of South Georgia, there was a fairly clear cut case for their elimination, but how many other islands could take such a simplistic view? Their ecosystems are more diverse, and it may be hard to argue what the balance could or should be – or avoid the unexpected consequences.

Anybody interested in such issues, or simply in better understanding what was done at South Georgia, will be able to discuss them at the Island Invasives Conference that will be held at the University of Dundee from 10–14 July this year.

9 – The South Georgia pipit is making a comeback, making all the efforts worthwhile. © Ingo Arndt

For Martin there is a satisfying symmetry to this.

There have been two previous conferences, held in New Zealand in 2001 and 2010. He attended the Auckland event in 2010 and was hugely impressed by the expertise of the host nation. ‘The Kiwis decided 20–30 years ago that unless they did something there would be no wildlife left,’ he said.

Then the New Zealanders shared their experiences; now it is Martin who is at the forefront. But probably not for long.

At the end of last year, the New Zealand government announced that it intends to eliminate all introduced predators – for which one can read all predators – by the end of 2050. Every rat, stoat and possum will go. It seems that the ambitious project in that funny island in the South Atlantic will have a greater resonance. Next stop UK?

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Technical

By Jack Brodie, James Hitchmough and Michael Livingstone

Planting for pollinators How can landscape practitioners best support UK native pollinating insects in urban landscapes?

Research at the University of Sheffield sheds light on this increasingly important topic.

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h ere is a crisis in the UK and many other developed countries: the decline of a wide range of insects that visit flowers to gather nectar and pollen. The twentieth century saw major population declines, range contractions and local extinctions of many wild insect pollinators such as wild bees and butterflies and also in managed populations of honey bees. This has

led to fears that the pollination services provided by insect pollinators, may be in danger of collapse. Indeed, there is a suggestion that the feedback processes behind this may already be occurring (Biesmeijer et al. 2006).

This would have dire consequences for agricultural crops, many wild plants, and ecosystems.

The decline of pollinators is due to a number of factors, but the single most

important is the greatly reduced number of flowers in the landscape (Roulston & Goodall 2010). This is mainly the result of the ‘green revolution’ of intensive agriculture in the twentieth century.

Many flower-rich habitats such as unimproved grassland, hay meadows, fallow fields, leguminous forage and hedgerows were lost during this period. This greatly reduced both the abundance and diversity of floral

1 – The near-native Origanum laevigatum (marjoram) is one of the most popular and very nectar rich plants in our study at the University of Sheffield. © Jack Brodie

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Technical

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resources available in the landscape, creating flower shortages in both space and time (Baude et al. 2016).

Ironically, given our historical belief that nature predominantly resides in the countryside, it is in arable landscapes that pollinators seem to have fared the worst, whilst urban areas have retained surprisingly resilient pollinator populations over this period (Senipathi et al. 2015) One recent study by Baldock et al (2015), even found that UK urban areas support greater bee diversity than adjacent farmland.

This suggests that designed landscapes can and do support pollinators, and that we as landscape professionals can do a great deal to maintain pollinator diversity.

Historically we have tended to see planting as either primarily for nature, or primarily for people. This is a redundant way to see planting design in twenty-first century cities; rather we should consider all projects and sites as potential opportunities to

provide pollinator services irrespective of where these sit on the nature-culture spectrum. So what are some of the key factors we need to consider in designing these plantings?

The geographic origins of species The belief that only plants that are native to the nation state in question can effectively support native pollinators is widespread. However, the fact that pollinators have fared so well in urban parks and gardens where most of the flowers are non-natives suggests that this idea is deeply flawed.

This notion of native superiority has more recently been bolstered by studies by the likes of Comba et al.

(1999) who found that plant cultivars with double petals tend to have reduced nectar rewards and hence attractiveness to pollinators. This then became conflated with the spurious idea that most non-native species in the horticultural flora are similarly

transformed and hence are no good for pollinators.

Some native species are excellent for pollinators and some are much less so; similar patterns are seen in non-native species. The non-native species that are least good are often those that have evolved to use pollinators that are very different to our own native ones, for example Penstemon barbatus and Salvia splendens, which are both adapted to hummingbirds that are absent in western Europe.

In ecological terms species can be thought of in relation to the UK as ‘native’, ‘near-native’, and ‘non-native’.

‘Near native’ plants are species that are not native to, in our case, the UK, but might for example be found on the Western European mainland, such as for example, Eryngium planum.

‘Non-native’ plants are more geographically distant still.

Nearly all UK ‘native’ plants and pollinators are distributed in other countries beyond the UK; we have virtually no UK endemics. For us these species are natives but they are also native to distant places. Galium verum, lady’s bedstraw and Geranium pratense, meadow cranesbill, for example naturally extend from the UK all the way to Mongolia, while the whitetailed bumble bee naturally ranges from North America to Japan. Many of our native pollinators, or insects very similar to them, will have naturally co-existed and co-evolved with many ‘near-native’ or even some ‘non-native’ plant species beyond our borders and are therefore, very likely to recognise these types of plant species as a resource.

However, in many cases ‘non-native’ plants are assumed not to have co-evolved with pollinators native to the UK, and hence in this situation are less likely to be of value to these. Clearly there are lots of ifs and buts in this – it’s a minefield of dubious assumptions that are only just beginning to be tested.

The good news is that there is a growing body of scientifically rigorous literature that quantifies the relative value of native and non-native plant species to UK pollinators. What this

2 – Eryngium (sea holly) is another of the most nectar-rich plants in our study © Jack Brodie

3 – Native pollinators using non native flowers; hoverfly on near-native dianthus carthusanorum ‘carthusian pink’. © Jack Brodie

data shows is that being valuable to pollinators is primarily dependent on the possession of certain biological characteristics or traits, which do not correlate neatly with original geographical distribution.

Recent studies by Hicks et al. (2016) and Garbuzov & Ratnieks (2014) have confirmed that non-native plants provide abundant and potentially very valuable resources. Salisbury et al.

(2015) and Hanley et al. (2014) have shown that native pollinators are just as happy, and sometimes even prefer, to use these non-native flowers when available. We have ourselves found, in our Sheffield trials, strong evidence for the ecological value of non-native plants and particularly near-natives.

As our climate warms and our ‘native’ pollinator assemblage changes (yes, some currently non-native pollinators will become new ‘natives’), some near-native and non-native plants will potentially become more valuable. Combined with the usefulness of non-native species

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in other aspects such as flowering season, aesthetic appeal and cultural importance, they should not be excluded from urban planting projects simply by virtue of their origin. Plant species should instead be valued for the specific traits and characteristics which make them demonstrably valuable to pollinators.

Value to pollinators; important plant characteristics and traits Nectar rewards The sugar concentration in nectar is a key determinant of flower quality for most pollinators, as nectar is a key source of energy. The second factor is the volume of nectar produced by different flowers; this has been seen to vary by at least two orders of magnitude, and some plants seem to barely produce any nectar at all (Hicks et al. 2016).

Clearly, plants that produce nectar with a high concentration of sugar and lots of it are potentially going to be highly attractive to many pollinators.

The protein composition of nectar can also be important, particularly for butterflies as this is their key source of adult nutrition. Nectar high in amino acids is believed therefore to be of higher quality.

In the most extensive survey to date, a team at Edinburgh University (Hicks et al. 2016) found that plants with daisy flowers (Asteraceae) provide most of the biggest nectar rewards per blossom. In particular, perennial yellow composites and thistles including several weed species were very good. However some non-daisies such as Malva moschata and Echium vulgare were also very good. Of course the exclusion of a species from one of these lists does not mean it is not valuable but simply that these lists of species reflect the assumptions and culture of the people running the study. In the Edinburgh study, for example, many of the species are native because it was undertaken by ecologists grounded in the belief that native species are good, but who also dabbled with some non-natives, the type of annuals found in pictorial meadows, because these were becoming increasingly familiar in cities.

Our own studies at the University of Sheffield, on stress-tolerant ‘steppe’ like plantings of mainly near-native species found, not surprisingly, that other types of flowers also offered highly valuable nectar rewards that were well used by pollinators. In particular, the near-native Origanum laevigatum and Eryngium planum were outstanding at the whole-plant level and Malva moschata (native), Stachys byzantina (near native), Potentilla nepalensis (non-native) are outstanding on a per-flower basis. In contrast, Lychnis coronaria, another European near-native species (listed as good on the RHS perfect for pollinators list) appears to provide no nectar at all. So much for geography of origin, with regard to nectar.

While other non-native species in our experiments, such as Oenothera tetragona and Penstemon barbatus, were largely ignored by pollinators despite presenting big nectar rewards, Landscape Summer 2017 47

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P. barbatus is regularly visited by bees in my garden; there are many factors in determining a plant’s value, including its context.

In more general terms, it seems from recent studies that perennial, as opposed to annual, herbaceous plants will, when not highly artificially altered, provide the most nectar. Those with large flowers provide more nectar per flower but less overall than those with masses of small flowers.

Pollen rewards Pollen is a particularly important resource for bees, who are pollen specialists, since they rear their larvae on it, but pollen is also used by hoverflies and flower-visiting beetles in their adult diets and is likely to be important for egg production in these groups.

Pollen quantities provided by different plants have been explored by Hicks et al. (2016) and are seen to vary by several magnitudes, from almost none produced in some plants to masses in others. In contrast to the

6

48 Landscape Summer 2017

4, 5 – Nectar and pollen accessibility; Salvia pratensis (meadow clary) with hidden pollen (black arrow) and nectar (white arrow) and Potentilla nepalensis (cinquefoil) with openly accessible nectar and pollen.

4 © Wikimedia Commons: K. Nell (2012) 5 © Jack Brodie

4

situation with nectar, annual species appear to provide more pollen resources than perennials. In Hicks et al.’s (2016) study, the most pollen-rich flowers were the annuals Eschscholzia californica, Californian poppy (non-native), and Papaver rhoeas, corn poppies (widely seen as native but most likely an ancient introduced non-native from central Asia). The main gauge of pollen quality is protein content, which Roulston et al. (2000) found to vary widely between species from 2.5% to 61%.

Bees will collect low-quality pollen but it can detrimentally affect their

5

health and larval development if too dominant in their diet, Whilst excellent for nectar, plants in the Asteraceae family typically have poor-quality pollen, whilst the pea family (Fabaceae) and Campanulaceae have highquality pollen.

Flower morphology One of the key specialising traits in a wide range of pollinators is the length of feeding mouthparts. If one selects plants with the nectaries at different depths within the flower, a diversity of pollinators can be supported. Deeply

6 – Our stress tolerant ‘steppe’ like experimental plantings at Green Estate, Sheffield. © James Hitchmough

7 – Popularity with pollinators of different plant species in our Sheffield study.

8 – Nectar sugar resource provided by different plant species in our Sheffield study. © Jack Brodie, James Hitchmough, and Michael Livingstone

Origanum laevigatum Eryngium planum Salvia pratensis Chrysanthemum max.

Campanula portenschlagiana Thymus polytrichus Malva moschata Scabiosa ochroleuca Campanula glomerata Stachys byzantina Knautia arvensis Potentilla nepalensis Centaurea scabiosa Scabiosa columbaria Erigeron glaucus Oenothera tetragona Betonica officinalis Gaura lindheimeri Geranium sanguineum Penstemon barbatus Lychnis coronaria Dianthus carthusianorum Knautia macedonica Heuchera sanguinea

0.0

5.0 Bees

10.0

15.0

20.0

Butterflies & moths

Flies

25.0

30.0

35.0

40.0

Other insects

7

Nectar sugar per flower (mu g) 0

1000

2000

3000

4000

5000

6000

7000

Origanum laevigatum Penstemon barbatus Eryngium planum Scabiosa ochroleuca Stachys byzantina Scabiosa columbaria Thymus polytrichus Betonica officinalis Knautia arvensis Oenothera tetragona Malva moschata Gaura lindheimeri Knautia macedonica Campanula glomerata Potentilla nepalensis Dianthus carthusianorum Geranium sanguineum Lychnis coronaria 0 8

100

200

300

400

500

600

700

800

900

1000

Nectar sugar per plant (mg)

Landscape Summer 2017 49

Technical

9 – Native pollinators using non native flowers; solitary wool carder bee (Anthidium maculatum) on near-native Stachys byzantina (lambs ear).

This is the bees’ favourite plant, which provides both food and nesting materials.

placed nectaries were preferred by bumble bees with longer tongues in our Sheffield field trials. Some complexshaped flowers restrict access to both nectar and pollen rewards to exclude all pollinators other than certain bee species. Examples of these include many pea (Fabaceae) species such as lupins and vetches but also some Lamiaceae like Salvia pratensis (meadow clary). In contrast to this, pollinators with less sophisticated or smaller feeding mouthparts, such as hoverflies, wasps and some solitary bees, need flowers with the more accessible floral nectaries and pollen that are found in flatter flowers such as Potentilla nepalensis and shallower flowers such as Eryngium and other Apiaceae family members.

Š Jack Brodie

Flowering times The human desire to have flowers over as long a season as possible fits in well with supporting pollinators. Longflowering species are potentially valuable because they help ensure continuity of supply. Early-flowering and late-flowering (autumn) species are also valuable as they provide nectar and pollen when few plants are flowering in agricultural or semi-natural habitats. For example, bumble bee queens first emerge in early spring when they start their colonies; late in the season the new bumble bee queens and butterflies need to fatten up for hibernation.

Non-native species are often particularly valuable at these times of year when few natives are in flower.

Putting these principles into practice In most cases in multi-purpose/value general urban plantings, it will not be possible to base plantings purely on the most nectar- or pollen-rich species from the research we have highlighted.

These species may not be appropriate to the site, the aesthetic and other functional requirements of the planting, or the management regime. A degree of compromise is therefore inevitable, and in many cases desirable.

50 Landscape Summer 2017

9

10 – Native pollinators using non native flowers; solitary leaf-cutter bee (Megachile centuncularis) on non-native Erigeron glaucus (beach aster).

This is the most popular plant for leaf cutter bees in our study, possibly due to its accessible pollen. © Jack Brodie

As we have discussed, species that are good for pollen, may be poor for nectar and vice versa. We are likely to be most interested in supporting a diversity of pollinator species rather than massive populations of one species, for example lavender and honey bees. To do this, diversity of plant species is key, using species that have medium to high sugar concentration and total volume of nectar, medium to high quality pollen, a diversity of floral forms, long flowering season, and a diversity of flowering times from early spring to autumn. Diversity is also likely to be important in spatial terms at the scale of the plantings; having different communities in different spaces is probably a better strategy for pollinator diversity than repeating a seemingly premier pollinator community everywhere. This is precisely why domestic urban gardens are so successful in supporting exceptionally high native invertebrate diversity; every

garden supports a significantly different plant flora. There is something somewhere for most invertebrates.

The scale of overall provision is also important; large areas of resource are ultimately able to support larger populations of pollinators than small patches can. At present the wealth of new scientific data on the attractiveness of plants to pollinators is beginning to provide more clarity on how to use such information in design, but is also raising questions about how to provide access to this and how to constantly update as new discoveries are made.

One approach could be the development of an open access trait database along the lines of the German BIOFLOR project, but more design orientated.

This could allow the maximisation of the ecological benefit of landscape planting projects without restricting creative, bespoke planting design by having to rely on pre-designed off the shelf mixes or specialist expertise.

References Baldock, K.C., Goddard, M.A., Hicks, D.M., Kunin, W.E., Mitschunas, N., Osgathorpe, L.M., Potts, S.G., Robertson, K.M., Scott, A.V., Stone, G.N. and Vaughan, I.P. (2015) Where is the UK’s pollinator biodiversity?

The importance of urban areas for flower-visiting insects. Proc. R. Soc. B, 282.

Baude, M., Kunin, W.E., Boatman, N.D., Conyers, S., Davies, N., Gillespie, M.A., Morton, R.D., Smart, S.M. and Memmott, J., (2016) Historical nectar assessment reveals the fall and rise of floral resources in Britain. Nature, 530.

Biesmeijer, J.C., Roberts, S.P.M., Reemer, M., Ohlemuller, R., Edwards, M., Peeters, T., Schaffers, A.P., Potts, S.G., Kleukers, R., Thomas, C.D., Settele J. and Kunin W. E. (2006) Parallel declines in pollinators and insect-pollinated plants in Britain and the Netherlands. Science, 313.

Garbuzov, M. and Ratnieks, F.L. (2014) Quantifying variation among garden plants in attractiveness to bees and other flower‐visiting insects. Functional Ecology, 28.

Hicks DM, Ouvrard P, Baldock KCR, Baude M, Goddard MA, Kunin WE, et al. (2016) Food for Pollinators: Quantifying the Nectar and Pollen Resources of Urban Flower Meadows. PLoS ONE, 11.

Roulston, T.H., Cane, J.H., Buchmann, S.L. (2000) What governs protein content of pollen: pollinator preferences, pollen– pistil interactions, or phylogeny?

Ecological Monographs, 70.

Salisbury A, Armitage J, Bostock H, Perry J, Tatchell M, Thompson K. (2015) Enhancing gardens as habitats for flower-visiting aerial insects (pollinators): should we plant native or exotic species?

Journal of Applied Ecology, 52.

Senapathi, D., Carvalheiro, L.G., Biesmeijer, J.C., Dodson, C.A., Evans, R.L., McKerchar, M., Morton, R.D., Moss, E.D., Roberts, S.P., Kunin, W.E. and Potts, S.G. (2015) The impact of over 80 years of land cover changes on bee and wasp pollinator communities in England. In Proc. R. Soc. B, 282.

Hanley ME, Awbi, AJ & Franco, M (2014) Going native? Flower use by bumblebees in English urban gardens. Annals of Botany, 113.

Credit The authors are all at the department of landscape, University of Sheffield.

10

Landscape Summer 2017 51

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Technical

By Colin Hambidge

Plane truths about tree disease A recent seminar on a disease that threatens plane trees highlighted some important points about how we think about our forests and about commerce 1 – Canker stain of plane is caused by the fungus Ceratocystis platani (syn. Ceratocystis fimbriata f. sp. platani). © Lucio Montecchio

1

L

a st autumn, Lucio Montecchio, professor of forest pathology and ornamental tree pathology at the University of Padua in Italy led a seminar on canker stain of plane trees at Barcham Trees. There could be nobody better qualified to do so, since he has been studying the topic for nearly 30 years.

The threat posed to Britain’s plane trees by canker stain of plane is growing, as it works its way northwards through France, travelling at a faster rate than previously thought. The problem is caused by an ascomycete fungus (Ceratocystis platani), which originated in the eastern United States. It reached the ports of southern Europe, most

probably on infected crating material, during World War Two, spreading rapidly through Italy, Switzerland and France. It was also reported recently in Greece and Albania.

Montecchio began by challenging the way we look at the threats facing our trees. When we talk of ‘fungal invasions’, do we really mean ‘invasions of cheap commodities’, he asked. The concept of plant protection and the legislation relating to it come from an anthropocentric perspective – not from a wish to save plants, but rather to reduce production losses. Do we really care about the health of forests as a whole?

Montecchio suggested that what we actually care about is the loss of

productive species. For example, we care for hazels when they are planted for nuts, but dislike them when they compete with beech in a firstgeneration forest.

He pointed out that we can go as far as to suggest deliberately spreading lethal, epidemic parasites in order to ‘biocontrol’ undesirable species. For example, inoculation with oak wilt fungus (Ceratocystis fagacearum) and treatment with chemical silvicides were compared as a means of eradicating oak trees in central Minnesota, USA, from 1953 to 1967. Inoculation with the fungus resulted in 92 to 99 per cent mortality, while application of chemical silvicides resulted in lower mortality Landscape Summer 2017 53

Technical

and higher cost.

If a forest is regarded as 100 per cent a natural ecosystem producing social and ecosystem services, then there are no crops to protect. In an unmanaged natural forest, a native parasite causes sustainable level of damage. These parasites invade and ‘de-invade’ forests, allowing both natural selection of the best biologically performing genotypes, and the geographic distribution of species.

Or, Montecchio asked, is a forest actually a human-assisted ‘income machine’? In that case where there is one product and one enemy, such as Chalara in an ash plantation, there is a need for crop protection. He suggested that in order to hide human responsibility, we call imported exotic parasites ‘invaders’. But is it a biologic invasion or an invitation to spread?

All living beings seek out the best.

All species, from fungi to humans, look for space and nutrients in order to survive, reproduce and spread. Where there is a high level of competition, migration is the answer. Colonisation strategies are the same in all creatures able to move spontaneously. But fungi have no legs or wings; they cannot travel thousands of miles in a few days to invade and colonise our plants.

Montecchio told his audience that it is the import of cheap commodities which is invasive, not exotic fungi; these behave merely as pioneers in a new world. When something is cheap, we buy it, including the poorest commodities, such as waste wood for biofuel, firewood and bark. Trade is the main means of the unnatural introduction of known and unknown pathogens. Most of the fungi with epidemic potential were and are imported from similar climatic areas through different commodities such as nursery stock, logs, seeds and packaging material.

An exotic, artificially introduced fungus can spread epidemically in a new environment, initially with no visible symptoms. Early warning, surveillance, contingency plans, plus rapid and efficient eradication measures, are needed at this stage.

54 Landscape Summer 2017

2 – Collection of a sample from a plane tree 3 – Damage on an affected plane tree © Lucio Montecchio

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4

But in a few years, the susceptible species decline and die, by which time it is often too late for anything other than containment. Of course, early warning, eradication and containment do not come free of charge, Montecchio reminded delegates.

What of the dozens of unknown species regularly imported and then reported as pathogens? Eradication measures could work, but not one of the quarantined forest fungi has been 100 per cent eradicated in the whole European Union. We are, he suggested, less efficient than legless microscopic fungi. What can we realistically do?

We can decrease the actual probability of introduction and spread.

First, in a science-based approach, known parasites must be studied before their arrival, according to climatic and environmental features, looking for vulnerabilities. There could be early warning and detection through multi-level surveillance, including at citizen level and through social media.

We also need inspectors with the right ‘toolbox’, including information, training, laboratories and other resources. It also needs a quick response at supranational level, so we are ready to move according to common contingency plans, have the financial resources available in advance and carry them right through to posteradication surveys, with no overlaps in responsibilities.

56 Landscape Summer 2017

Platanus acerifolia (the London plane), a vigorous, hardy hybrid of Platanus occidentalis and Platanus orientalis, was produced around 1670 in the Oxford Botanical Garden.

The selection of a few, quite similar genotypes across Britain accelerated during the Industrial Revolution, mainly thanks to their tolerance of air pollution.

In a few decades, the London plane was planted all over Europe and the USA – in gardens, parks and avenues.

But with clonal selections, important features are enhanced to the detriment

5

of others, such as susceptibility to unknown parasites.

The later arrival of chainsaws, and the large, slow-closing cuts they produced became an open invitation to wound parasites such as Ceratocystis platani. The artificial spread of London plane in southern Europe and the trans-oceanic import of Ceratocystis platani resulted in the meeting of two perfectly compatible partners.

The spread of the fungus in Europe was mainly through infected sawdust and pruning tools, Montecchio emphasised. The lack of disinfection of tools after pruning infected trees is the main infection pathway across long distances, due to the long-term viability of the fungus on sawdust residues on chainsaws. ‘The disease is effectively spread by uninformed contractors involved in infected plane pruning, and their infected chainsaws’, he said.

There is no cure for this humanassisted disease. Prevention and containment are the only efficient ways to slow down the spread of this parasite.

Movement of plants for planting and non-squared wood from countries where the disease occurs is prohibited.

Colin Hambridge is a gardening writer

4 – An affected plane tree 5 – Detailed view of the canker stain organism © Lucio Montecchio

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Technical

By Sebastien Miller

Heat gain and paving selection It is well known that some surfaces become hotter than others, but now there are quantified results showing how much impact different materials have on the urban heat island effect.

R

eports stating that 2016 was officially the hottest year on record reinforce the trend of ongoing and accelerated global warming. In the Middle East, air temperatures have been slowly increasing, reaching a summer high of 50.5°C in the Emirate of Abu Dhabi during 20151 and a scorching 54°C in Kuwait during 20162. Some projections suggest that the rate of warming in the Middle East is increasing 50% faster than the global average and that by 2071, cities could regularly experience days in excess of 45°C, with occasional peaks of 60°C3.

When reading these figures, you must remember that climate modelling is not exact and that there is disagreement among leading scientists about the rate and severity of global warming in the Gulf region. Nevertheless, landscape designers should take every possible 58 Landscape Summer 2017

step to create more resilient cities, including by making appropriate selections of materials. To this end, I recently undertook investigations into the thermal effects associated with material density in paving. Most designers already know that certain materials are hotter than others but what I hope to provide is quantifiable evidence showing the amount of heat gain associated with the selection of different materials and finishes.

Figure 1, opposite, shows temperature recordings for each material, colour and finish. These experiments were recorded with an infrared temperature gun at five specific times throughout the day.

Two sample areas were laid, one in full sun and the other in full shade, with measurements carried out over a four-day period during the beginning of June. This provided average readings,

which eliminated unusually high recordings that could skew the data in any particular direction.

Rate, intensity and duration of heat gain While peak temperatures give a snapshot of the worst-case situations, it is more useful to understand the thermal performance (heat gain / heat release) of different materials throughout the course of the day.

Figure 2 shows the heat gain for different materials throughout the day.

The temperatures are noted in degrees Celsius, and represent the average of readings of all materials, regardless of colour or finish. Each material was exposed to full sun in early June (summer). Sunrise was at 5:45am and sunset at 6:52pm. There was no cloud cover: none. Humidity was 35–39% throughout the day.

Materials such as timber and marble peak before midday, yet remain only 1.2–2.4°C warmer than the recorded air temperature in the late afternoon.

Limestone slowly warms up throughout the morning, peaking by mid-afternoon before it cools to 0.8°C above the evening air temperature.

Granite and asphalt absorb significant heat very rapidly, reaching peaks of 12°C higher than the midday

air temperature. Not surprisingly, asphalt is the worst contributor, and remains 8°C hotter, even in the early evening when people are most likely to use public spaces in the Middle East.

If designers were to approach Middle East projects with the aim of increasing ambient heat by an extra 2–12°C, and making the public realm less comfortable for users, we would be ridiculed. Yet by ignoring thermal

properties, we do that for almost every project. We look at aesthetics and durability (ensuring projects photograph well), but pay far less attention to user comfort.

The graph in figure 3 shows the extent of heat gain and its duration for different materials. This is specific to the Gulf region and is based on the recorded temperatures as noted in figure 2. The air temperature (grey)

Figure 1: Peak temperatures of different materials

Material

Colour

Finish

Temperature full sun (highest average reading)

Temperature full sun (highest individual reading)

Temperature 100% shade (highest individual reading)

Asphalt

Black

Rough

52.0

53.8

37.5

Granite

Black

Honed

59.0

61.4

39.9

Granite

Black

Sand blasted

56.0

57.2

39.8

Granite

Dark grey

Honed

56

61.1

39.5

Granite

Dark grey

Sand blasted

54.5

60.0

39.0

Granite

Mid grey

Honed

50.5

58.8

38.1

Granite

Mid grey

Sand blasted

46.5

50.7

39.1

Granite

Light grey

Honed

44.0

48.2

38.1

Granite

Light grey

Sand blasted

42.0

44.6

37.0

Granite

Buff / cream

Sand blasted

45.0

51.4

36.4

Sandstone

Buff / cream

Honed

46.0

51.6

35.8

Limestone

Buff / cream

Honed

40.0

41.6

36.6

Limestone

Buff / cream

Sand blasted

40.0

42.1

35.1

Marble

Buff / cream

Honed

45.0

47.3

36.6

Pre-cast concrete

Dark grey

Sand blasted

54.5

57.3

39.1

Pre-cast concrete

Mid grey

Sand blasted

48.7

55.0

38.7

Pre-cast concrete

Light grey

Sand blasted

45.0

47.3

36.5

Pre-cast concrete

Buff / cream

Sand blasted

45.1

51.4

35.5

Timber (natural)

Brown

Grooved

45.5

46.0

36.1

Timber (natural)

Brown

Smooth

47.00

47.6

36.5

Landscape Summer 2017 59

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Figure 2: Heat gain for different materials throughout the day

Time Air temperature

32.0o

40.0o

39.5o

36.0o

31.0o

Asphalt temperature

31.5

52.0

51.2

46.0

39.1

Road Interlock paving (concrete) temperature

32.7

42.2

49.0

44.2

35.2

Granite temperature

34.5

51.9

50.3

41.9

33.2

Sandstone temperature

32.7

43.7

46.0

37.2

31.8

Limestone temperature

32.5

37.6

42.1

36.8

31.7

Marble temperature

34.4

45.0

44.6

37.4

31.9

Pre-cast concrete temperature

33.6

43.2

49.3

42.8

33.8

Timber temperature

32.5

46.8

45.9

38.4

–

is provided as a baseline comparison.

Figure 4 demonstrates the way that different materials respond to the rate of heat absorption, the intensity of heat gain, and the duration of heat release. Analysis of the recorded temperatures demonstrated four key characteristics, which are differentiated by heat absorption, intensity and duration. This is based on the recorded temperature graph as noted in Figure 3.

Figure 5 shows a housing development in the UAE that uses pre-cast concrete blocks (Heat Gain-3 (HG-3) rating) to minimise the urban heat island effect. Such a material choice reduces public realm temperatures by almost 4°C in the evenings and 7.8°C at peak times.

Other benefits of pre-cast concrete blocks are that they create more pedestrian-friendly streets visually.

They also reduce vehicle speeds slightly, as higher speeds (60km+) create a noticeable vibration effect and noise for drivers. In contrast, granite (HG-4 rating and shown in Figure 6) can reach temperatures of just over 60°C at mid-day, while concrete (HG-3 60 Landscape Summer 2017

8.30am 11.00am 2.00pm 5.00pm 7.00pm

rating) can reach temperatures of just under 50°C. In hot climates, such materials should never be considered for seating or planter walls, as these temperatures are physically painful to the human touch. Schemes that do not consider basic human comfort will fail in a warming climate.

Gravel aggregates, as seen in Figure 7, have recently become popular for Middle Eastern landscapes, for use instead of grassed areas. While this is a brilliant water-saving approach to

design, little consideration is given to the urban heat island effect. The materials specified are almost always granite or gabbro on account of their low cost, durability, and availability on the market Unfortunately, granite is rated HG-4 and can contribute to the urban heat island effect by 7°C or more. A more environmental approach would be to use crushed limestone (HG-1), which would only contribute to the UHI effect by 1–2°C. 1 – Figure 5: UAE housing development that uses pre-cast concrete blocks (HG-3 rating) to minimise the urban heat island effect. © Sebastien Miller

1

Figure 3: Extent and duration of heat island effect

Asphalt Granite Timber Marble Pre-cast concrete Sandstone Concrete interlock Limestone Air temperature

Figure 4: The heat gain (HG) effect for different materials.

Peak temperatures HG-1 Material with low heat gain (2–3o C) and peak temperature occurring in the afternoon (ie: Limestone)

HG-4

HG-2 Material with medium heat gain (4–6o C) and peak temperature occurring mid-morning (ie: Timber)

Temperature

HG-3

HG-3 Material with high heat gain (7–9o C) and peak temperature occurring in the afternoon (ie: Concrete)

HG-2

HG-1

Morning

Afternoon

Evening

HG-4 Material with extreme heat gain (10–12o C) and peak temperature occurring mid-morning (ie: Asphalt)

Time of day

Landscape Summer 2017 61

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2

Conclusion In order to reduce the impacts of climate change and build resilience to our cities, designers should look at limiting or avoiding HG-4 materials. While this may not always be possible in the face of performance and cost-related issues, there are some very ordinary projects that have achieved this.

Poor material selection has the potential to add 20°C to localised hardscape temperatures and, on a wider scale, it will be certain to contribute to the urban heat island effect. With some scientists estimating that we will have Middle East summer temperatures that regularly exceed 45°C 3, are we faced with living and working in cities that have a real temperature of 55–60°C when combined with the effects of poor material choice?

Landscape architecture is not just a matter of contributing to better quality and aesthetically pleasing urban environments. It also relates directly to reducing the energy costs and carbon footprints of our cities, while at the same time increasing user comfort. As our planet continues to warm and cities get larger both in area and density, this is an issue that needs to be taken seriously.

Sebastien Miller has 15 years’ experience in landscape architecture, public realm and urban design. He is currently working from the Broadway Malyan studio in Abu Dhabi while studying his MSc. in urban and regional planning.

3

62 Landscape Summer 2017

References 1 Abu Dhabi, National Center of Meteorology & Seismology; 2 UN, 2016. Temperature in Kuwait hits 54 celsius. Available from: www.un.org/apps/ news/story.asp?NewsID=54559#.

WF4X2HfpNAY; 3 World Bank, 2016. Adaptation to a Changing Climate in the Arab Countries.

As referenced in www.thenational.ae/uae/ environment/too-hot-to-live-in-the-gulfdont-be-so-sure;

2 – Figure 6: Granite can be attractive but is problematic in terms of heat gain.

3 – Figure 7: Gravel aggregates reduce the need for watering, but cause other problems. © Sebastien Miller

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Culture

By Ben Gosling

Landscape as Infrastructure The LI conference in Manchester in June will examine all aspects of this vital topic

1 – Manchester skyline © Wei Deng

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I

n his 2014 Review of Architecture and the Built Environment, Sir Terry Farrell observed that ‘In order to create the kind of high-quality places we all want, a major cultural change is needed where the focus of everyone involved moves towards the wider context of what is already there and its all-important setting and context.

‘Landscape’, he continued, ‘is the primary infrastructure.’

Landscape as infrastructure is a vital theme for the LI, and we will explore it in detail at this year’s conference.

Landscape is not just about creating spaces, but transforming them: about harmonising disparate elements in a way that creates value and addresses the needs of everyone. Whether climate change and the environment, green infrastructure, health and well-being or natural capital, the intervention of the landscape profession can benefit society on every level. Our annual conference will be a lens through which we can scrutinise, promote and debate the issues central to the needs of our members’ clients and 64 Landscape Summer 2017

the wider public.

By recognising the importance of landscape as infrastructure, the LI seeks to weave together achievements in resilience, flood prevention, public health and more, highlighting the public good that practitioners do, whether through design, planning or management. No matter their discipline, our members operate in the natural interface between people, their

environment and infrastructure.

It is time not only to recognise and celebrate this, but to determine how best we can use our skills to create the sustainable future society needs.

The conference will take place over two days. Day one will consist of a mix of hour-long plenary sessions and breakouts, and on day two, delegates will attend site visits to some of the most innovative and exciting

2 – Central Manchester’s new tram system has had a major impact on public realm © Wei Deng 3 – Chenshan Botanic Garden Quarry Walk – one of the projects to be showcased at the conference © Yufan Zhu 4 – Chenshan Botanic Garden © Yufan Zhu

infrastructure projects in Manchester and Salford. The plenary sessions on day one are structured in such a way as to build a cohesive narrative, developing the brief of landscape as infrastructure throughout the day: 1F rom the Humber to the heart of China, the first session will examine where people and nature meet: large-scale regeneration, densification and urban parks, the building of flood defences, and the destruction of landscape character by urbanisation.

2 The second session explores how turning infrastructures into ecological networks can lead to massive ecological restoration initiatives. The ever-changing definition of landscape and its role as infrastructure allows practitioners to address challenges of carbon creation, habitat destruction and deteriorating public health.

2

3 The value of landscape is well known, but rarely understood.

Natural capital accounting will be of immense importance to the profession in coming years, as by demonstrating the value of green infrastructure, we will be able to fully unlock its benefits. The third session discusses in detail the applications, and implications, of the natural capital initiative.

4 The final session deals with social infrastructure; the places where we meet, eat, shop, relax, protest; the places where our communities form and thrive. It examines the changing face of our city centres and the part landscape practitioners can play in transforming our cities for the better, and looks at the role landscape can play in welcoming refugees and nurturing children.

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Followed by a reception.

The LI Conference 2017 will take place at Manchester Metropolitan University on 22 and 23 June. For more information about key themes, plenary sessions, speakers and other activities, visit the Landscape Institute website, www.landscapeinstitute.org.

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Landscape Summer 2017 65

On my mind

Speaking up for the profession I am learning from others about how to promote my business, and this has broader lessons for the profession I set up a landscape practice, ETLA IN March, (Eleanor Trenfield Landscape Architects), and I have been overwhelmed by the support and opportunities that have come my way so far. But whilst I would consider myself skilled at what I do, the business-development side of my new role has been more of a learning curve.

So, I decided to appoint a business development consultant, to review my plan for how to increase my profile and support me in turning all these leads and opportunities into appointments. She was a warm, talkative and clearly a skilled person in her field, reinforcing this with the phrase ‘I am shit hot at what I do’. Her lack of modesty came as a surprise.

It made me think that perhaps our modesty within the landscape profession is doing us a disservice given the loud and media-savvy world we are operating in. We need to be selling ourselves and the brand of landscape architecture more.

She was very clear about what a professional needs to do to raise their profile in their respective industry. A professional needs to put him / herself out there, write and publish, be active on LinkedIn or relevant industry platforms, speak at events, and attend networking events, all of which are obvious but we are all busy, and all too easily use this as an excuse. As landscape architects we should all be doing more writing, speaking and networking, we need to ‘lean in’ and we need to encourage an environment in which opinion and debate are welcomed.

The Landscape Institute news, blogs and Journal provide a platform that I encourage all members to use more. Let’s all lean in and promote the landscape profession, and get involved with the Landscape Institute within councils, technical committees, branches etc.

Please, start writing and speaking at events, and let the world see that we are ‘shit hot’. We need to build a stronger brand to strengthen our standing in the industry and recruit the next generation. And the Landscape Institute needs to support us in doing this, by developing a stronger identity for the profession.

Eleanor Trenfeld is honorary editor of Landscape and director of ETLA.

© Tom Lee

Perhaps our modesty within the landscape profession is doing us a disservice.

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66 Landscape Summer 2017

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