Conference Speakers 2025

Trees and homeowners’ insurance: Adoption of climate-smart tree risk assessment in coastal communities

The threat of tree failure damage to coastal communities is related to increasing frequency and intensity of storms. Preliminary evidence suggests that insurance companies are implementing policies that could influence community forest management decisions. These policies include increasing premiums, denying coverage, or suggesting the removal of trees, all of which represent a negative adaptation to climate change because not all trees are vulnerable to storms. Proper management activities, such as appropriate species selection and placement, pruning and tree healthcare, can mitigate risk. In turn, a healthy and abundant tree canopy is a critical step towards climate change resilience.

To this end, our research will: (1) describe current trends in insurance-motivated tree risk reduction activities; (2) identify the industry’s risk assessment methods and communication of risk to arborists and homeowners; (3) document homeowner response to tree risk. The study uses a mixed methods approach of interviews with insurance professionals and Certified Arborists across the US South to identify trends and risk communication. In addition, homeowners, insurers and arborists will complete surveys measuring risk perceptions and relationships with insurance and tree management.

The disconnect in tree risk knowledge and decision-making among insurers, and the lack of communication between professionals, has created an atmosphere of distrust. Despite the rift that exists between many arborists and insurance carriers, several interview participants from both industries expressed a desire to bridge gaps and create better working relationships. My presentation will identify the policies and practices used by the insurance industry to mitigate its risk, and develop opportunities for the insurance and tree care industries to increase their knowledge about tree risk and management as well as improve working relationships.

Biography

Beau Brodbeck is an Assistant Director for Field Operations and an Affiliate Faculty in the College of Forestry, Wildlife and Environment at Auburn University. He began his career as a forestry consultant before becoming an Urban Forestry Specialist at Auburn University managing Alabama’s hurricane recovery programme in the aftermath of Hurricanes Ivan and Katrina. Over the past few years, he has developed educational outreach programmes and publications. His research has focused on the human dimensions of urban forest management as well as migrant labour within the forest industry.

Wood decay from a material perspective: Insights from recent studies and experimental research

Fungal degradation of wood in standing trees remains a highly debated and complex topic, with significant implications for tree health assessment, urban forestry and structural stability. While much research has been conducted, the biological mechanisms behind wood degradation are not yet fully understood, and the interaction between wood properties, environmental factors and fungal activity continues to raise critical questions, particularly in urban environments.

In our research, we have investigated wood degradation from a material perspective, analysing its effects in both laboratory and field conditions. Our findings, published in various scientific journals, highlight the differing behaviours of multiple fungal species in relation to different wood species and demonstrate how wood degradation influences the outcomes of non-destructive assessment methods. One of our key research sites includes trees artificially inoculated with two relevant fungi, allowing us to observe degradation patterns in a controlled field environment.

However, an essential question remains: why do wood degradation dynamics in urban environments differ from those in natural settings? Can the answer be found at the material level of wood? Addressing these questions, this presentation will summarise our research findings from recent years and introduce interim results from an ongoing two-year study focused on wood degradation in urban environments. Through a material-based approach, we aim to deepen the understanding of degradation processes and their implications for tree stability assessment.

Biography

Valentino Cristini was born in Italy and moved to the Czech Republic in 2013 to pursue university studies in arboriculture while gaining practical experience as a tree climber. After graduation, Valentino worked in arboricultural consultancy and applied phytopathology before beginning PhD research on changes in acoustic and mechanical properties of green wood due to fungal activity. Valentino is an assistant professor specialising in tree care in urban environments and carries out research into wood decay at the material level, integrating biomechanics, pathology and advanced diagnostic methods.

Tree allometry: What is it and how can we use it to improve arboriculture?

In 2024, we produced the Handbook of UK Urban Tree Allometric Equations and Size Characteristics.

This was the product of analysing a large set of measured tree data contributed by Treework Environmental Partnership and other organisations. The allometric equations presented in the Handbook enable the production of 2D and 3D models of trees, including projected growth, derived from one or two measured attributes.

Our presentation will explore:

• What is allometry?
• How the study arrived at the calculations.
• What are the issues with the data that we will overcome with future studies?
• A visual presentation of how the allometric equations are used to model 2D and 3D trees and tree canopy growth, CAVAT value and carbon sequestration over time.

It will also be call to action: the arboricultural profession has an amazing opportunity to utilise the data that we have collected on trees to improve our knowledge and practice of tree care.

Biography

Luke Fay is a Senior Arboricultural Consultant with over 30 years’ experience. He leads a team of consultants at Treework Environmental Practice working on award-winning regeneration projects and large tree planting projects as well as providing advice on nationally important ancient trees. He also works to raise the profile and practices of the sector as part of a number of initiatives including the Landscape Institute Digital Practice Group, the London Tree Officers’ Association Diversity and Inclusion Working Party and the CAVAT Group.

Joe Fennell is a geospatial data scientist with specialist expertise in vegetation remote sensing. He has a background in plant sciences (PhD, Lancaster Environment Centre) and held research posts at the University of Manchester and the Open University. He supports diverse organisations in the development of insights from their geospatial and environmental datasets.

Changing Tasmania’s giant tree culture

Tasmania’s giant eucalyptus trees have long been a curious mystery to most tree enthusiasts around the world. The island’s remoteness, the expense of travelling there and limited shared knowledge have meant that the story of Tasmania’s world-class giant trees has remained a secret.

Other factors, like an extensive old-growth forestry industry and a movement of environmentalists both fighting over the forests, have also contributed to wider society knowing very little about these trees.

The Tree Projects shares the stories of these giants and has spearheaded several movements that have resulted in better awareness and protection for these huge trees.

Biography

Steven Pearce is an award-winning photographer and filmmaker and is the creative director for The Tree Projects. Willing to push the boundaries and embrace the latest technologies, he is able to deliver content that is unique, beautiful and inspiring. As an avid tree climber and a passionate naturalist, he has spent over 10 years documenting trees and forests.

Allergenic potential of pollen produced by trees

The flowers of some tree species produce pollen that can induce an allergic reaction, and preventing high pollen concentrations in the air is very relevant for allergic patients.

When deciding which tree species to plant, it is important to take pollen allergenicity into account. The available guides are very diverse in content and interpretation – and the content often depends on the part of the world you are living in and the methodology used. In our study, a guide was developed for the allergenic potential of trees in the Netherlands. Knowledge of the allergenicity of tree pollen was collected for the most common species, as well as an inventory of regional pollen abundance. At the same time, data from a patient group with inhalation allergies was analysed. Allergenicity was classified into five categories, from very strong allergenic potential to low. This methodology was developed to provide a region-specific guide to classifying the allergenic potential of tree pollen. The possible uses of this guide, which is not intended to create a new witch hunt, are diverse and could be beneficial for people with tree pollen allergy. It will help landscape designers make sound decisions to create healthy living spaces.

Biography

Wendy Batenburg is a scientific researcher. She is involved with research and development at Terra Nostra as a project leader, conducting field trials and performing diagnostics on tree-related diseases such as phytophthora and sooty bark disease. For her research on sooty bark disease, she received a European Arboricultural Council grant. She is also an i-Tree specialist, develops new techniques in arboriculture and is involved in the management of the oak processionary moth and the grant project related to allergenicity of trees.

Towards risk based-surveillance strategies in tree health

The occurrence of tree pests and diseases has increased greatly since the industrial revolution, driven by anthropogenic factors such as human-mediated transport and environmental stresses. This results in damage to culturally significant species and wider ecosystem functioning, as well as economic losses. The effective detection of such pests and diseases is critical to counter this threat.

Through early detection, we can increase the probability of eradicating a pest and decrease the overall costs of management. Effective detection also enables better understanding of the distribution ranges of diseases and thus their causal agents, which can be complex and multi-factorial. Many technological advances have been made in diagnostics, e.g. through DNA detection and remote sensing, but people remain critical. People are around trees every day, either through professional work or leisure, and both professional visual inspection and citizen science reports remain fundamental in tree health. However, unlike other forms of disease diagnostics, the reliability of visual tree health inspection is not routinely quantified. Without this information, it is not possible to make basic interpretations of surveillance data such as the confidence that a pest/disease is absent, or the likely true distribution of a pest/disease. Such data therefore has important implications for devising effective risk-based surveillance strategies. In addition to understanding the reliability of detection methods, it is also critical that we understand how pests are likely to arrive and spread, but this becomes more complex with an increasing number of biotic and abiotic stresses.

This presentation will first cover the work undertaken to quantify the reliability of visual inspection in tree health and then, using the case study of ash dieback disease and emerald ash borer beetle, examine the likely influence of an already endemic tree disease on the spread of a potential future pest.

Biography

Matt Combes is a research fellow and tree epidemiologist at the University of Warwick. He has expertise in ash dieback disease and authored a review article on the current understanding and future prospects of the disease in Britain. His work at Warwick in the group run by Dr Stephen Parnell, in collaboration with organisations including Rothamsted Research and Forest Research, has involved projects quantifying the reliability of visual inspection in tree health, examining fungal pathogen adaptation to disease control measures, and modelling the potential impacts of ash dieback disease on emerald ash borer beetle.

Flying in the face of oak processionary moth

It has been nearly 20 years since oak processionary moth (OPM) was introduced to the UK. With it came fears of tree damage and human health risks. Despite many millions of pounds being spent on its management, OPM is now naturalised in Greater London and will continue to spread. For many tree managers within the established zone OPM has become a normal part of risk management.

Since 2015, the team of conservation arborists at Hampstead Heath have been managing OPM in a busy urban open space. In 2018 we began monitoring the numbers of parasitoid insects, predominantly tachinid flies emerging from OPM nests. Initially this was to investigate any possible links between populations of OPM and the predatory tachinid fly Carcelia iliaca. Some years later, the number of species we have found predating OPM has increased, producing more questions than firm answers. However, the main question that we are asking is will nature-based solutions generally prove to be the most satisfactory method for controlling OPM?

Oak processionary moth has not been the major problem we feared it could be. I would like to share some of the findings from our seven-year ongoing parasitism study and ask you join me in looking to explore the possibilities of implementing a risk- and nature-based approach to managing OPM.

Biography

Alasdair Nicoll is a conservation arborist for the City of London specialising in managing and working on ancient and veteran trees. He has spent over 20 years working in commercial and local authority arboriculture. His focus on ecological arboriculture has led him to explore holistic methods of managing OPM on a busy urban site.

What do we know about Armillaria? The tangled taxonomy of a tree killer or ecosystem engineer?

Amongst arborists, perhaps no other fungus elicits as much attention as the notorious honey fungus, but is its bark worse than its bite? And do we truly know who we’re dealing with?

Over a century of study and a tangled taxonomy have framed Armillaria species as merciless killers of trees, but in some forested systems millennium-old individuals of Armillaria have developed stable coevolutionary relationships with whole ecosystems. This presentation explores the history of Armillaria research, reframing Armillaria from destructive pathogen to keystone species, exploring the taxonomy, ecology pathobiology and control of Armillaria.

From roots to rhizomorphs, is Armillaria due a rethink?

Biography

Ed Pyne has over a decade of combined academic and arboricultural practitioner experience. He holds a PhD in Fungal Ecology from Bangor University where he investigated antagonistic interactions between Armillaria and wood-inhabiting saprotrophs, focusing on the chemical, ecological and genomic mechanisms underpinning these interactions. His research focus includes fungal community ecology, veteranisation and fungal biocontrols. He is currently the senior conservation advisor for trees at the Woodland Trust, where he provides scientific expertise in the evidence-based conservation of ancient trees.