Highlights of the UK’s biggest arboricultural conference, which this year was held online for the first time.

THE Arboricultural Association’s 54th National Amenity Conference took place online across two days in early September. It was hoped the event would take place at Loughborough, but unfortunately it wasn’t to be. However, the fact the conference was held online did present the opportunity for an international line-up of speakers – from Madrid, Greece and Italy to Florida, Toronto to Nova Scotia – to come together and discuss the theme of Trees & Society.

Writing in the conference programme, CEO of the Arboricultural Association, John Parker, said: “Arboriculture is often just as much about people as it is about trees. How people interact with trees, what trees mean to them, and the often-complex relationships between people and trees in urban areas should all be considerations for anyone who works with, or is interested in, amenity trees.”


Monday’s morning session kicked off with the University of Florida’s Rob Northrop presenting on ‘Incorporating social science into arboricultural and urban forestry decision making’.

“Each urban forest is different, having come into its present state through unique history and an interactive set of ecological and social events,” he explained.

The urban forest is distinct due to the high density of human habitation, leading to more complex social interactions, increased variation in land cover and landform modification, and a greater degree of public control of land use and management.

So, why the present focus on urban forests? Using his home state of Florida as an example, Rob highlighted three trends he believes are causing people to think more about them: the growing breadth of metropolitan regions globally, urban densification, and the immediate impact urban forests have on the lives of people.

Forestry Journal:  University of Florida’s Rob Northrop University of Florida’s Rob Northrop

“People have now made managing the urban forest a priority. They are increasingly finding greater and greater value in the urban forest. It is important to also recognise that urban forest science is motivated by social values. These social values are leading science to investigate the values of the urban forest – increasing our knowledge of the social values it provides.”

Catherine Nuttgens, community forestry manager for Sheffield City Council presented on community forestry in the city. There are 3.9 million trees within the city boundary and seven trees per head of the population, which makes the city one of the most wooded in the UK, even though the unwooded Peak District National Park falls in a significant area within the city boundary.

Catherine explained: “Community forestry has been around for about 20 years. It started off being about specific projects in specific areas, usually around engaging young people in tree-planting in schools and communities. It has adapted through the years to fit into different initiatives.”

The team was significantly reduced as result of austerity but is now beginning to grow again. However, there are still numerous challenges, Catherine said. These include: a number of constraints on public land limits and space to plant, how success is measured (‘tree numbers not necessarily being the best measure of success’), a lack of funding, multiple managers of Sheffield’s trees, and risks to tree survival such as extreme weather.

And there is a lot to do going forward, including: obtaining funding, public engagement, maximising opportunities in council and city region wide partnerships, and exploring commercial opportunities such as tree nurseries and agroforestry.

Claudia García-Ventura, Ms Forestry Engineer and tree risk consultant for the Council of Madrid, presented on her study into the characteristics of urban trees most valued by citizens.

This survey included two parts: the first on sociodemographic variables; the second one with questions about the importance of the variables or characteristics of the trees, scoring from 1 (no importance) to 10 (maximum importance).

After three months, 128 responses were obtained. The aspects citizens value the most about trees were found to be pollution reduction, temperature damping, and the importance of the canopy size in maximising these benefits.

Helen Davies, associate director – nature capital at Logika Consultants, presented on Citizen and business attitudes towards urban trees and the ecosystem services they provide. Despite the wide range of ecosystem services that urban forests provide to society, austerity measures mean local government budgets for tree-planting and maintenance have declined in many cities. A potential solution to this could be the adoption of a beneficiary-pays model – payments for ecosystem services.

Helen’s research posed the question: do the beneficiaries of urban forests value trees enough to want to pay for them? This question was answered through interviews with 30 businesses and a survey of 415 citizens in the UK city of Southampton.

Delving further into the question of why and how urban trees are important to people – and what happens when they are removed – was Camilo Ordóñez of the University of Toronto.

Forestry Journal: A truly international event, the conference saw presentations focusing on urban trees in regions as diverse as Florida, Madrid and Sheffield.A truly international event, the conference saw presentations focusing on urban trees in regions as diverse as Florida, Madrid and Sheffield.

He presented results from an experimental investigation measuring how the social and ecological benefits provided by urban trees change before and after trees are removed from parks and streets. The study used selected park and street sites in the Cities of Melbourne, Ballarat, and Moreland, Australia, to investigate changes to density of birds and other fauna, tree herbivory, tree attitudes and preferences, subjective human wellbeing, and nature connectedness of the people visiting the sites.

Such research, he said, can give cities the tools to quantify how much social and ecological benefit is lost due to tree removal, so they can more effectively account for tree losses and protect their urban forests.

The value of trees and best how to quantify it was also the focus of Peter Duinker from Dalhousie University, utilising i-Tree Eco analysis from the city of Halifax, Nova Scotia and comparing it against feedback from residents.

His major recommendation for those involved in budgeting for urban forest work was: “Do not ignore the incalculable.”

He said: “The range of values on people’s minds is way, way larger than what is calculable using the i-Tree software.”

This is particularly important when local politicians are deciding budgets as they are more likely to be influenced by the sentiments of their constituents. The monetary values attributed to trees are typically irrelevant in an urban setting.

He said: “It is good to spend money on urban forest management because the majority of urban residents, who are the constituents, want a maintained or improved population of trees in the city.

“Most urban forest values are appropriately understood in qualitative terms, not quantitative terms, and decision makers like municipal councillors have no difficulty coping with qualitative indicators associated with what their constituents want. 

“Urban forest managers should have a much stronger understanding of how urban forest dwellers value the trees in the city. That can drive both funding propositions and management decisions.”


Stefania Gasperini opened the afternoon session with a look at veteran trees and ‘ethical arboriculture’, highlighting empathetic practices in Italy, where dignity has been returned to ancient trees with the granting of ‘inalienable rights’.

Ted Green MBE delved further into this topic, calling for real acknowledgement of the importance of individual trees which have played critical roles in history. 

He pointed to five examples – the Parliament Oak in Sherwood Forest, Kett’s Oak in Norfolk, Allerton Oak in Liverpool, the Wye Oak in the USA and the Tolpuddle Martyrs’ Tree – which prove trees should not be taken for granted, least of all by arborists, who are the people best-placed to ensure specimens of historic significance do not go unrecognised.

He said: “We have committees that sit around thinking about what to do about an important tree. There’s never an arborist at the table. They’ll get a special report, but then they’ll sit around interpreting what the arborist has said. And in every case I’ve seen, the can gets kicked down the road because, while they recognise the tree is important, they can’t make a decision, because they’re not arborists.Equally, I’d like to point a finger at the arborists and ask: what are you doing about it?” 

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The Woodland Trust’s citizen science officer Tom Reed spoke on the Ancient Tree Inventory, a citizen science project which aims to identify and map the oldest and most important trees across the UK.

Explaining how it is being used today and how it could help in the future, he said: “Mapping these trees is the first step towards their long-term protection. If we don’t know where they are, we can’t help protect and restore them.”

Continuing with the theme of citizen science was the Woodland Trust’s Rebecca Gosling, who explained how it, along with the Observatree tree health early warning system and Nature’s Calendar could utilise the help of the public to protect the UK’s woods and trees.

Explaining the benefits of using citizen science, she said: “In 2019 alone our three citizen science projects generated over 27,000 reports on trees – and that number is going up annually. We’re generating data, rapidly reporting non-native pests and diseases, evidencing climate change and protecting ancient and veteran trees.”

Jessica Stocks, tree officer for the Royal Borough of Kensington & Chelsea, turned the focus onto the workforce, with an argument for why diversity matters. Explaining the aims of the LTOA Diversity Working Party, she encouraged attendees to be proactive in encouraging difference in the sector. 

Arguing that diversity “improves our sector with diverse thinking and innovative ideas” she called on arborists to implement the actions in the LTOP Diversity in the Workplace report (www.ltoa.org.uk/docs/ltoa-diversity-report.pdf).

Dimitris Tsimplinas took attendees on a journey through time with a tour of the urban trees of Ancient Greece, with further insight offered from Anastasia Petsi, delving into their role in Greek mythology.


Day 2’s morning session opened with a presentation from Clare Hall of Forest Research on how different types of engagement with trees and greenspace can lead to learning, new knowledge and skills development.

Focusing on three UK studies (an evaluation of Observatree, an evaluation of Mission: Invertebrate and a visitor study at Bedgebury Pinetum), she said three key questions had been raised, namely: 
•    Does new knowledge about environmental actions lead to habitual behaviours?
•    What is the significance of new knowledge versus building on existing knowledge and interests?
•    To what extent can informal activities lead to learning?

She asked: “Do practitioners need to fund these big programmes like Mission: Invertebrate etc, in order to help people learn, or is it enough just to encourage and enable people to access green space in order to help them learn?”

Dr Neil Strong, biodiversity strategy manager for Network Rail spoke about work being done to re-establish a railway hedge at Hadley Wood on the East Coast main line.

Detailing how trees and foliage had been considerably cut back from the track (outraging local residents), he said: “Work was too enthusiastic. We weren’t able to communicate we were doing the right thing in the right place. As a result, the impact on residents was quite massive and we had to react to that and start working with the community to see what we could do.”

A collaboration with the Tree Council and the Hadley Wood Rail User Group resulted in the laying down of a trial to re-establish a hedgerow alongside the operational railway, comparing techniques of direct seeding, whip planting and natural regeneration.

Does the utility arb sector have a bad reputation? This was a question pondered by Andy Gardner of EOS Contracting during his presentation, which looked at the rise of modern utility arboriculture and the techniques it uses to manage the UK electricity network.

Forestry Journal: Network Rail’s Neil Strong told how the removal of trees alongside the railway at Hadley Wood, Hertfordshire, resulted in a furore that helped bring about the Varley Review of Network Rail’s lineside vegetation management.Network Rail’s Neil Strong told how the removal of trees alongside the railway at Hadley Wood, Hertfordshire, resulted in a furore that helped bring about the Varley Review of Network Rail’s lineside vegetation management.

“The investment over the last 20 years by the electrical sector and pioneering sector-specific training programmes has created a sector of highly skilled utility arborists, contract managers and safety professionals, all within our sector. But we haven’t always got it right.”

Sharing evidence of brash left in public areas, side pruning to the sky (and not to appropriate growth points) and examples of pruning not done to BS3998 and ‘runway’ clearances, he said: “The standards are not brilliant. And that, unfortunately, is the reason why we’ve had bad press.”

However, as additional regulations and standards have been introduced through the Energy Network Association along with changes in regulation, the approach to how trees are managed around electrical networks has improved, with advances in technology being utilised to ensure the infrastructure is managed in a sustainable, safe and compliant way.

Forestry Journal:

Berglind Karlsdóttir of Forest Research looked at how apps like the Shaun the Sheep Glow Trail could be used to encourage families to be more active in nature, while Lucio Montecchio of the University of Padova, Italy, explored how messages around tree health and biosecurity could be spread – and sometimes twisted – through social media. He highlighted examples from Facebook of non-experts providing dangerously inaccurate diagnoses and treatments for diseased trees.

“All of us have a collective responsibility for tree health,” he said. “Spread of scientific knowledge, biosecurity protocols, communication by real experts and efficient, prompt control measures must be priorities.”

The Orchard Project’s Jo Homan concluded the morning session by detailing ways in which the project, which started in 2016, has successfully engaged with urban communities to provide the skills and confidence to growing and harvesting their own orchards.

Focusing on training and its impact on individuals, she said: “Orchards are fantastic places for learning, with so many things you can teach people about. We’ve developed a course called Certificate in Community Orcharding, attracting a really good mix of people. It’s quite a demanding course, but we’ve found the more you ask from people, the more you get from them.”


Carys Alder of Trees for Cities presented a case study measuring the effectiveness of trees and green infrastructure in reducing children’s exposure to exhaust fumes at four of London’s most polluted schools.

Much of the work involved landscaping and planting greenery in playgrounds to provide lower-pollution zones (or ‘green oases’) for pupils during breakdowns, with ivy used to create pollution barriers along school fences. The programme was shown to have improved awareness and understanding among pupils of air pollution and how to mitigate their exposure to it.

Carys said: “Green infrastructure can be used in a variety of ways. From our perspective, we have been using it to reduce exposure to pollutants through barriers and green oases, and also as part of a wider behavioural change programme, which has been really powerful.”

Tom Ogren, from the Society for Allergy-Friendly Environmental Gardening (SAFE Gardening), offered a different angle on the subject of plants and pollution. He explained how urban air pollution causes pollen grains from trees to fracture, becoming much smaller and being inhaled deeper into the chest, causing asthma. This issue had been exacerbated by ‘botanical sexism’, which led to the planting of more pollen-spewing male trees than female in cities, because they didn’t drop seeds or fruits. He said those who plant trees in urban areas owe it to residents to take more care in which kinds they plant.

“Allergies are increasing in all urban areas, worldwide,” he said. “Food allergies get a lot of attention in the media and people seem to take them seriously, but they don’t take pollen allergies as seriously. But food allergies, because of cross-reactivity, are related to pollen allergies. For example, in Europe, a popular tree is the silver birch. But if you get allergic to the pollen from silver birch you can develop 25 different food allergies. As such, I would suggest we stop planting birch in cities, or plant very few.”

The role trees, woodlands, and forests played in people’s responses and reactions to the COVID-19 lockdown was the focus of a study presented by Mandy Cook of Forest Research. With limited entertainment options for people during the pandemic, getting out and about in nature became an activity undertaken by many. Forest Research surveyed thousands of people to find out what form this activity took and how it helped them adapt to the stresses and strains of lockdown.

In his talk, Neville Fay of Treeworks Environmental Practice posed the question: ‘What is tree eco-politics?’

With indigenous peoples around the world dying while defending their forests, he asked attendees to consider the role of the tree sector in responding to environmental challenges.

“Some are making far bigger sacrifices in attempting to protect and restore ecological degradation than others. Equitability at a planetary level is something we need a greater understanding of. We should wake up to the fact that people are making sacrifices not only on their own behalf, but on behalf of our global systems. We’re at a crossroads and the question is: How can we deal with this?”

Looking to the future, Alan Simpson considered the potential for urban forestry to improve and support life in urban communities. His presentation specifically considered the issues associated with climate change, in particular the urban heat island effect, and the contribution urban forestry could make to mitigating it.

He said: “As well as being a landscaper and urban architect, I’m also an urban designer, and I’m very conscious of the fact that for a hundred years or more, we’ve been promising people urban utopias and we haven’t delivered.”

Delving into the pressing issue of climate change, he said: “The urban heat island is a big issue. Roads and buildings absorb the heat of the sun during the day and emanate it out at night, increasing temperatures. This is especially a problem in cities with a high concentration of structures and very little green. The temperature of a human being is around 37 degrees Celsius. Four degrees more than that, you’re talking about potential organ failure. But we know Greece, Italy and part of Catalonia all reached over 40 degrees this summer. So we’ve got to start thinking about this very carefully.

Forestry Journal: Anna-Maria Pálsdóttir of the Department of People and Society at the Swedish University of Agricultural SciencesAnna-Maria Pálsdóttir of the Department of People and Society at the Swedish University of Agricultural Sciences

“Trees are one of the most cost-effective ways of moderating urban temperatures. Trees cool their surroundings, casting shade and reflecting solar radiation, but if you look at the trees in our cities you’ll find many of them haven’t been planted at all well.”

The final presentation of the conference came from Anna-Maria Pálsdóttir of the Department of People and Society at the Swedish University of Agricultural Sciences.
She presented details of a vocational training programme in Southern Sweden which taught nature conservation skills to long-term Swedish unemployed and migrants. She told how participants perceived the activities as meaningful work and they had helped migrants feel more rooted in Swedish society.

“This is helping Sweden to meet its European-level nature conservation requirements and commitments and helping get people out of an urban setting and into nature which they otherwise wouldn’t connect to. This touches on public health and is good for cultural exchanges, social connections and friendship.”

Following a final Q&A, John Parker brought the conference to a close by saying: “This conference has been very different to anything we’ve done before, but I think you’ll agree the content has been as strong as any we’ve ever had. I’d like to thank our main sponsors, the Woodland Trust and Tree Life, and our supporting sponsors Greenfix and Ezytreev.

All of the presentations from this year’s conference are available to view on demand via www.conference.trees.org.uk.