Conference Speakers 24

Biography

Clive Mayhew is a Fellow of the Arboricultural Association who has worked in arboriculture since the early 1990s as a practitioner, a local government officer and an independent consultant. A long-standing advocate of custodial arboriculture, he sees tree professionals as fleeting caretakers of the trees and landscapes in their care. This prompted his desire to learn more about the trees we inherit. Much to his surprise, this research has expanded into a millennium-spanning, global story, stretching from ancient Mesopotamia to the Americas, from the Amazon to the Sussex Weald. It is also a story that contains many strikingly familiar themes for the contemporary practitioner.

 

Abstract

Trees have been cultivated, maintained, felled and converted for millennia; lightweight chainsaws have only been around for about 50 years. So what exactly did our arboricultural ancestors do before the option of reaching for the pull chord (or flicking the ‘on’ switch) became so universal?

This wide-ranging presentation will use archaeology, geology, art, photography and written records to reach a more holistic understanding of the factors which shaped the individual trees we have inherited, the landscapes they inhabit and the people who worked them. It will explore the drivers for tree work and timber conversion techniques from the earliest civilizations to the 20th century.

What sort of arboricultural tasks were undertaken in the past, and exactly how were those tasks achieved? The pre-eminence, decline and ultimate disappearance of axe work in tree maintenance will be considered, along with the importance and subsequent decline of splitting and cleaving as a conversion method. And what impact did the development of handsaw and ‘long’ saw technology have with regard to work on individual trees, coinciding as it did with the development of arboriculture as an identifiable discipline?

Finally, the presentation will consider the potential impact of historical work on the trees we manage today – or, indeed, on the way we manage them.

Biography

After working as an arborist climber for 10 years, Benoit de Reviers is now an arboricultural consultant. He has a Master’s degree in human sciences and educational sciences, and has worked around the world, including in Canada, the USA, Australia and Sweden. In 2018, he created Arbres & Solutions to provide advice and consultancy services on amenity tree management. He is working on ‘a modern approach to arboriculture, based on clinical diagnosis and methodical tree risk management, with the aim of better preserving our tree heritage’ and provides solutions for, and training in, the installation, management and control of bracing systems.

Abstract

Benoit de Reviers presented to conference 2023 on the state of knowledge and current practices in tree cabling and bracing. He will return in 2024 to explain new tools, materials and installation methods in this area of tree care. Benoit has developed equipment that is specifically adapted to new cabling practices and a mobile application for managing and monitoring bracing operations.

Biography

Jesse Coleman is the owner of Kōwhai Treecare. With a professional tenure in the industry spanning 15 years, Jesse has dedicated a substantial portion of this time to working in various corners of the globe, living out the quintessential arborist’s dream. Throughout Jesse's career, they have been fortunate to engage in and lead extensive projects, often involving cranes and helicopters. However, the most fulfilling and enjoyable aspect of their work is pruning and taking care of mature trees. In May 2018, Jesse made the pivotal decision to return to New Zealand and embark on the journey of establishing their own company.

 

Abstract

The Mauao Blackhawk project in New Zealand involved heli-lifting 26 large trees growing on the remains of three areas of cultural and historical significance. The site’s sensitivity, its location, and the sheer size of the trees made this a unique and challenging task for the team, which ultimately resulted in the successful completion of the project.

Biography

Aaron Shearer is an International Society of Arboriculture Certified Arborist who holds an MSc in arboriculture and urban forestry. He has worked in a variety of roles in arboriculture and urban forestry, but in recent years his career has taken a dramatic change. He moved to Iceland two years ago and since then has worked for the Icelandic forest service on a multitude of projects. He is currently based in the certification department. Because of his interest in urban forestry, he has also conducted an array of research into the structure of Iceland’s urban tree canopy.

Abstract

Forestry in Iceland has many unique attributes when compared to other parts of the world, but foresters globally all share the same desire to plant new forests and manage existing ones to the highest standards. To achieve these standards they must first understand the resource they are trying to manage, and when it comes to the forests of Iceland there is a wealth of data and publications to call on. Alas, this is not true for the urban forest. In fact, is there an urban forest in this land famed for volcanoes and glaciers?

Research has shown the important role urban trees play within the green infrastructure of any municipality, providing a bounty of ecosystem services alongside ecological and societal benefits. Unfortunately, it does not take long to realise that the available literature gives a limited understanding of urban forest structures in Iceland’s towns and cities. The lack of data drastically hampers attempts to form management plans, inform legislation or calculate ecosystem and asset value, whilst also hindering the ability to mitigate future threats.

In this presentation, Aaron Shearer will draw on his personal experience and research to delve into what exactly the Icelandic urban forest looks like, the threats it faces and the possibility of avoiding mistakes made by others in the past.

Biography

Aleksandra Zienkiewicz has been the co-ordinator of the Municipal Green Spaces Management Authority in Wrocław since 2018. She is responsible for cooperation in planning and strategic documents, the Green Patronage donors’ programme (Zielony Mecenat) and collaboration with NGOs. Educated in environmental protection and spatial planning, she is also a Certified Tree Inspector and has been promoting trees in the cityscape since 2014. She is the founder of Treecity (miastoDrzew) (a tree protection association) and leader of Wrocław’s Participatory Budget tree projects. She initiated and led the campaign to prevent the modification of tree protection law in Poland (2016) and co-authored social amendments to new regulations to minimise their negative consequences.

Abstract

Focusing on the diverse aspects of tree planting and young tree establishment in Wrocław, and how they have changed in recent years, this presentation will introduce the city’s Municipal Green Spaces Management Authority and the strategic and operational initiatives it has implemented to manage the urban forest more effectively.

It will explore the number of trees felled and why they have been removed, as well as setting out figures for new planting and the constantly developing standards for establishment of young trees. Soil assessment and conflicts with underground infrastructure will be considered, along with the authority’s experiences of planting different species and strains. The presentation will also set out problems with pests and diseases and other challenges, especially those connected to climate change such as heatwaves and drought, heavy rainfall and flash floods. Additionally, it will show the impact of the Participatory Budget and Green Patronage programme for donors on tree planting in the city.

Biography

Jonathan Fulcher is an ex-tree surgeon, ex-tree officer and now an arb consultant in private practice. He has written thousands of reports since 2002 and over 600 decisions for Planning Inspectorate TPO appeals: ‘Every day I'm engaging with clients and prospective clients and tree officers and architects, telling stories, helping people see what’s going on and how we might come to a successful outcome.’

Abstract

People love stories. They have been a way for us to connect for thousands of years, and we can use that in our working lives to better connect and engage with our audience. Many of us have a message of some kind that we want to get across – arborists and consultants want to get new clients, technical people have new theories they want to try, everyone needs funding. How do we make ourselves distinctive? We tell a story.

It doesn’t have to be complicated, but a narrative with a beginning, middle and end is what people like. We can apply that everywhere – to a fee quote, to a report, to an invoice, to a bid for resources and funds, to an abstract for a conference presentation.

This presentation will explore a brief of history of storytelling before moving on to narrative structure and ways of developing the range of places where narrative, at whatever scale, could make a difference in the way the message is received and understood.

Jonathan Fulcher wants to tell you a story…

Biography

Reg Harris is an arborist and consultant of nearly four decades whose primary focus is veteran and ancient tree work. He also specialises in habitat pruning (veteranisation). He is renowned for his work at sites including Sherwood Forest (Nottinghamshire) and Hatfield Forest (Essex) where he has helped develop and champion new techniques for managing and pruning veteran and ancient trees.

Abstract

Two years ago, whilst undertaking aerial tree work to some ancient hornbeam pollards in Essex, Reg Harris stumbled upon an intriguing discovery: unusual cankers and fungus within the upper crown of a tree.

This presentation will chronicle the journey of identifying a fungus and tree disease that is new to the UK and explore hornbeam decline’s potential implications for the management of ancient and veteran trees. It underscores the need for heightened vigilance in monitoring the health of hornbeam populations across the country. The potential spread of hornbeam decline could have far-reaching consequences for the species' conservation and management, as well as implications for the wider arboricultural and horticultural sectors that are reliant on the tree for various purposes.

Biography

Henry Kuppen is an arboricultural consultant from the Netherlands with over 40 years of professional experience in managing trees in the urban environment. He specialises in the management of pests and diseases using a holistic approach. He works as Tree Ambassador at Terra Nostra, a knowledge centre for trees and soils. He is actively involved in educating established and new-generation professionals about the maintenance and importance of trees and tree work as supervisor at the European Arboricultural Council. Henry is an accomplished public speaker who shares his knowledge by giving passionate talks and workshops to other professionals around the world.

Abstract

Sooty bark disease has been confirmed in the Netherlands and Belgium since 2014, and it has been present for much longer in the rest of Europe. Although the fungus was introduced to the UK from North America in 1945, it seems to have been forgotten in the regular management of maple species here. Following a study tour to the Netherlands in 2023, sooty bark disease was once again identified in the UK.

The disease is caused by the fungus Cryptostroma corticale and is mainly diagnosed on sycamore, Acer pseudoplatanus. Its spores – which are generated in huge numbers – can cause chronic pneumonitis in those who come into contact with the organism and do not protect themselves against spore inhalation. In addition to the fact that the fungus is latent in maple, it enters a tree through wounds and causes typical symptoms which can help with identification. Spore development is mainly stimulated by a decline in the condition of the tree, prolonged drought, and temperatures above 20°C. To be sure that a maple is affected by sooty bark disease, the spores must be analysed to determine whether they match a specific set of morphological characteristics.

To improve management and safety in the Netherlands, a health and safety protocol was issued by the Dutch national health and safety service Stigas and Terra Nostra. This document describes how personal protection (PPE) should be applied when processing a tree with sooty bark disease, and scientific research has confirmed the effectiveness of PPE in these circumstances. In addition, practical guidelines were drawn up to help tree officers manage sooty bark disease.

Henry Kuppen will explore the challenges of managing and working with infected trees.

Biography

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Abstract

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Biography

Dr. Kathleen Wolf (University of Washington, Seattle USA ) has built a multi-decade research program about human dimensions of urban forestry. Publications are aimed at building better knowledge of the social and psychological benefits that city trees provide, and sharing that across non-traditional audiences, including business, public health, medicine, and urban planning. Recent work has included One Health collaborations about the intersection of biodiversity and human health. Kathy has collaborated with international partners, and presented her research at conferences on all continents except Antarctica (maybe one day?). Nature and Health research is summarized at Green Cities: Good Health: http://depts.washington.edu/hhwb/

Abstract

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Biography

Jim Handley has been involved in horticulture for over 20 years. He started his career at F.P. Matthews, where his interest in trees began. He trained at Moreton Morrell College and the Royal Botanic Gardens, Kew, and he has recently completed the RHS Master of Horticulture qualification. He is Head of Gardens & Landscape at Grimsthorpe Castle where his varied role involves managing 70 acres of gardens and historic avenues as well as assisting with the management of over 300 acres of SSSI woodland pasture and limestone grassland.

Abstract

Grimsthorpe Castle in Lincolnshire is an historic estate dating back to the 13th century. It has evolved through the centuries and now comprises a Grade I listed house, gardens and a park with large areas designated Sites of Special Scientific Interest (SSSI), making it nationally important both historically and ecologically.

During the 17th century many tree-lined avenues were created through the parkland at Grimsthorpe as was the fashion, and many endure to this day, having been rejuvenated during the 19th century. The surviving avenues are in varying states of decline and an investigation is underway to consider factors important to avenue rejuvenation, in addition to trialling potentially suitable new tree species for avenue use at Grimsthorpe.

Biography

Dr Ryan Klein is an Assistant Professor of Arboriculture at the University of Florida. He has 12 years of experience in the nursery and tree care industry. Ryan has received the International Society of Arboriculture (ISA) Arborist Certification, Quantified Tree Risk Assessment (QTRA) Certification, ISA Tree Risk Assessment Qualification (TRAQ) and Prescription Pruning Qualification (PPQ). He is the Past-President of the Arboricultural Research and Education Academy (AREA) and sits on the Florida Chapter of the ISA Educational Board. His research focuses on tree risk assessment and risk perception, as well as the impacts of natural disasters and climate change on urban tree populations.

Abstract

Co-author: Howard Beck

Urban trees commonly suffer from high mortality rates and infrastructure conflicts due to improper species selection. This can lead to a loss of tree benefits and an increase in the associated maintenance costs. The Florida Trees website provides recommendations that assist the user in matching suitable tree species to specific site conditions. It also connects the user to external arboricultural resources where other relevant content can be found.

In 2021 the website ceased to function when Adobe Flash went off line; it had not been updated since 2011. It was subsequently recoded to meet current technical specifications and now houses species-specific information (e.g., mature size, flower, etc.) for approximately 1,200 species and incorporates both above- and below-ground site attributes (e.g., soil, size of planting space, etc.) throughout the selection process.

Unlike other online tree selection tools, the Florida Trees website has an AI expert system that integrates hundreds of rules and questions which are used to guide the user to a list of suitable species for a given site. Essentially, it is designed to render a list of species that follow the best practice of ‘right tree, right place’. The system that drives the website can be a useful tool for not only the public, but also tree care professionals, landscape architects and municipal land managers as they make site-specific planting decisions. The guidance it offers can help to maximise tree benefits and reduce maintenance costs.

This presentation will provide an overview of the project and describe the methods that were used to update the website and bring it back online. It will also identify other potential avenues where AI could be used to assist arboricultural professionals.

Biography

Kenton Rogers is a Chartered (Urban) Forester with a Masters in forest ecosystem management. In 2011 he co-founded Treeconomics, an urban forest consultancy. During his career he has worked on a range of community and urban forestry projects in the UK, Europe and North Africa. Kenton was a Trustee of the International Tree Foundation for 10 years and is a Fellow of the Royal Geographical Society. He was a contributing author for the Urban section of UK National Ecosystem Assessment and the Springer Urban Forest Handbook. More recently he co-authored the Haynes Manual for Trees.

Abstract

Co-authors: Kevin Frediani and Keith Sacre

Over the past year, a series of interactive workshops entitled ‘Finding your way through the urban forest’ have been conceived and delivered across the UK. Recognising the challenge of making sense of the abundant information available is important, as is addressing the need for a navigable approach that provides structure to a potentially overwhelming level of written advice. These workshops have tried to guide tree officers and land managers through all this information, as well as offering a comprehensive strategy for effective tree, woodland and urban forest management.

This presentation encapsulates the key findings from a year of collaborative learning and knowledge-sharing. Through the lens of experiences shared by experts and practitioners, these valuable insights have been distilled into actionable strategies for sustainable treescapes. Furthermore, the workshops served not only as a forum for strategic planning but also as a nexus for building a community of practice. Attendees have had the opportunity to interact, share their experiences, and glean wisdom from peers, fostering a network that extends beyond the confines of the workshop space.

This presentation will highlight the emergence of common challenges faced by diverse urban environments and the innovative solutions that have been collectively brainstormed. It will showcase the solutions generated during the workshops, providing tangible examples of how participants have translated knowledge into actionable urban forestry initiatives.

Join us as we reflect on a year of collaborative learning, celebrating the diversity of approaches, and charting a way forward for urban forest planning.

Biography

Originally a climbing arborist, then a consultant and trainer, since 2015 Philippe Trouillet has been running a consultancy and training centre in France. He now specialises in clinical mechanical and tree risk assessment. Philippe has a Master's degree in Education Sciences and his research thesis allowed him to investigate professional attitudes in arboriculture. He also explores using engineering methods (scoring, management strategies, auditing), and has published a number of articles in professional journals.

Abstract

There seems to be consensus in the arboricultural community about why using a t/R = 0.3 threshold is not sufficient to assess a tree's safety factor. However, a large number of arborists around the world are still using it. Why?

An assessor who is aware of the limits of using a threshold probably feels that they have to justify why they sometimes don’t apply it. This justification is often based on quantifying the safety factor using technological tools such as tomography or pulling tests. But is this instrumentation always justified? Is it possible to refine the assessment of the safety factor without using technological models, by making the reasoning more complex?

The human and medical sciences have long explored these questions, and have come up with tried-and-tested answers such as clinical scores. These scores assist the clinical assessor in confirming or refuting a diagnosis. For professionals, the objective is to move away from the subjective and the intuitive. As arborists, we must now move away from the visual tree assessment approach, which is far too intuitive, and adopt more sophisticated methods that combine several parameters. Rigorous, robust and scientific approaches are now available to arboriculture.

 

Biography

For at least 30 years Jill Butler has had a specialist interest in ancient and other veteran trees and ancient Forests, wood pastures and parkland. This interest has led her into exploring and understanding the history and structure of past landscapes through ancient trees. Jill is a qualified VETcert Consultant. She is also a keen surveyor and verifier for the Ancient Tree Inventory, a project hosted by the Woodland Trust in partnership with the Tree Register of the British Isles and the Ancient Tree Forum. She is a Trustee of the Forest of Selwood and the Tree Register of the British Isles.

Abstract

The UK has a great legacy of old historic avenues, which retain many original trees, owing to the long history and importance of designed landscapes surrounding high-status mansions. The avenue as a spectacular feature and status symbol rose to special prominence and popularity in the 18th century under the influence of the great landscape designers such as ‘Capability’ Brown and Humphry Repton.

This presentation will make the case for the retention of old, historic avenue trees. The removal and replacement of such trees should be resisted, especially all the trees in a short space of time, just to rejuvenate the design feature. This results in the loss of irreplaceable habitat on an unsustainable scale. Now, more than ever, the need for retention and conservation management is overwhelming, given the biodiversity and climate crises facing the world. At a time when there are so many calls to plant trees, it seems incomprehensible to remove trees which are already well established and working hard at ecosystem and tourism services.

If landscape designers and site managers are seriously underestimating the habitat value and heritage significance of old trees, there is a role for stakeholders (e.g. arboriculturists, agency advisors, the Trees and Design Action Group) to influence their thinking. ‘Thinking arbs’ well versed in how to care for such ageing trees should be involved in decision-making and speaking up for their irreplaceable values. The debate should be about how best to prolong the trees’ lives and their values and should challenge any further loss of ancient and other veteran and heritage trees.

Biography

Dr Claudia Canedoli is a researcher at the Landscape Ecology Laboratory in the Department of Earth and Environmental Sciences at the University of Milano Bicocca. She holds a PhD in urban ecology and her background is primarily focused on the quantification and mapping of ecosystem services within terrestrial ecosystems, especially urban and natural forests. Her current work centres on bridging gaps in biodiversity knowledge, investigating biodiversity associated with trees, species relationships, and reducing conflicts between humans and trees in urban areas.

Abstract

Co-presenter : Davide Corengia

How many species of organisms live on a single tree? What are these species and how do they interact with the tree itself? Ecology has plenty of questions that still need answers. With a team of ecologists and arborists, Claudia Canedoli and Davide Corengia have begun a research project financed by the Maisons du Monde Foundation aimed at addressing these challenging issues.

Urban forest trees are essential: they maintain biodiversity, deliver fundamental ecosystem services and are ultimately major contributors to a city’s resilience. Habitat trees harbour the highest level of biodiversity, but they are also the most threatened in urban landscapes and this constitutes a major problem in biodiversity conservation. This project has described the biological communities of a number of trees in Milan, identifying the whole variety of life from microorganisms (fungi, bacteria or algae) to mosses and lichens, invertebrates, and vertebrates. The results show the presence of thousands of organisms spanning different taxonomical groups.

This presentation will explore the seasonal turnover of communities, which change significantly during the year, and also the vertical patterns of species occupancy. Biodiversity changes according to vertical structure, for abundance and diversity, and this varies across different organisms. This information is very important for tree care specialists: pruning or branch removal may have a great impact on biological communities.

The project has also tested a sampling protocol to help replicate surveys. The results are crucial for raising awareness of conserving habitat trees in urban areas. A website has been created to convey the message (www.biotreeversity.com) and an exhibition entitled ‘A Journey Around a Tree’ will be hosted by the Natural History Museum of Milan from September to November 2024. This will constitute a unique opportunity for citizens and experts to debate this topic.

Davide Corengia is a European Tree Worker and works in projects aimed at integrating biodiversity conservation measures into tree management practices. He founded Biotreeversity, an action community which studies, manages and communicates the importance of trees by considering the biodiversity associated with them. He collaborates with various research projects including the creation of artificial nests for bats, birds and insects and tree biodiversity surveys. He is a member of SIA, the Italian Chapter of the International Society of Arboriculture.

 

Biography

Davide Corengia is a European Tree Worker and works in projects aimed at integrating biodiversity conservation measures into tree management practices. He founded Biotreeversity, an action community which studies, manages and communicates the importance of trees by considering the biodiversity associated with them. He collaborates with various research projects including the creation of artificial nests for bats, birds and insects and tree biodiversity surveys. He is a member of SIA, the Italian Chapter of the International Society of Arboriculture.

Abstract

Co-presenter : Claudia Canedoli

How many species of organisms live on a single tree? What are these species and how do they interact with the tree itself? Ecology has plenty of questions that still need answers. With a team of ecologists and arborists, Claudia Canedoli and Davide Corengia have begun a research project financed by the Maisons du Monde Foundation aimed at addressing these challenging issues.

Urban forest trees are essential: they maintain biodiversity, deliver fundamental ecosystem services and are ultimately major contributors to a city’s resilience. Habitat trees harbour the highest level of biodiversity, but they are also the most threatened in urban landscapes and this constitutes a major problem in biodiversity conservation. This project has described the biological communities of a number of trees in Milan, identifying the whole variety of life from microorganisms (fungi, bacteria or algae) to mosses and lichens, invertebrates, and vertebrates. The results show the presence of thousands of organisms spanning different taxonomical groups.

This presentation will explore the seasonal turnover of communities, which change significantly during the year, and also the vertical patterns of species occupancy. Biodiversity changes according to vertical structure, for abundance and diversity, and this varies across different organisms. This information is very important for tree care specialists: pruning or branch removal may have a great impact on biological communities.

The project has also tested a sampling protocol to help replicate surveys. The results are crucial for raising awareness of conserving habitat trees in urban areas. A website has been created to convey the message (www.biotreeversity.com) and an exhibition entitled ‘A Journey Around a Tree’ will be hosted by the Natural History Museum of Milan from September to November 2024. This will constitute a unique opportunity for citizens and experts to debate this topic.

 

Biography

Menno Kluiters has been climbing trees professionally for 25 years and has been privileged to work alongside many skilled and passionate arborists worldwide. As a keen young man, he enjoyed nothing more than cutting trees down. That was until he met other weathered role models who, he says, ‘made me realise the beauty and value of trees. After five years “under my belt” (harness), my real captivating tree journey had only just begun. Now, after dwelling in canopies for many years, more and more tree-related patterns are recognised and understood. Even though I’m no spring chicken, I still thoroughly enjoy hanging out with my woody friends, high up in the canopy, and long may it last. These days my goal is to provide better tree care and pass on the knowledge that trees have shared with me. After all, the trees remain my greatest teacher.’

Abstract

New Zealand endured cyclone Gabrielle on 13th and 14th February 2023. Tairāwhiti/Gisborne was one of the regions especially hard hit, with multiple recordings of rainfall of over 600mm during that time. With the ground already saturated, rivers burst their banks causing unimaginable damage to infrastructure and property. This extraordinary event led to numerous whole-tree failures, but very few were due to high winds as you would expect from a cyclone.

The region’s geology is the most erosion prone in the country and tops the charts internationally. Indeed, most trees failed due to erosion or more accurately whole hillside collapse. This has led to unique failure patterns and this presentation will highlight them, presenting case studies on single trees, erosion in old-growth forest and silt deposits.

 

Biography

Julian Forbes-Laird has been an arboricultural consultant since 2000, having previously worked for 10 years as a climbing arborist. He is a Chartered Arboriculturist and a member of the Institute of Chartered Foresters, the Royal Society of Biology, the Royal Institution of Chartered Surveyors, the Expert Witness Institute and the Arboricultural Association. He is Chair of the British Standards Institution’s technical committee B/213 (Trees & Tree Work) and a Licensed Lecturer in Visual Tree Assessment for the Karlsruhe Institute of Technology.

Abstract

Surveying trees

Julian Forbes-Laird will explain the nature and role of the two types of lignin in furthering the diagnosis and prognosis of wood decay in trees, with reference to the moisture relations of relevant fungi. The presentation will describe how the type of lignin is related to tree type (angiosperm or gymnosperm); the nature of the supporting wood (tension or compression); the hydrodynamic structure of the tree (Stages I–IV); and the resulting resistance and susceptibility of the tree to decay of different types.

Existing, but little-known, information has been collated from different sources and used to construct a new framework for understanding and managing decayed trees: Substrate Moisture Classification. The SMC framework is likely to be particularly helpful in cases where the pathogen species is unknown, whilst also serving as a guide to further understanding of host/agent interactions, and thus the management decision.