Arboricultural Association
Conference 2026

7th–9th September
LANCASTER UNIVERSITY

Sponsored by:

Emma Gilmartin, Senior Technical Officer

It’s that time again. Booking is now open for our annual Conference in September, and we’re delighted to be heading to the north-west of England.

This year’s event will be hosted by Lancaster University within its vibrant and attractive campus just 3 miles south of the historic city of Lancaster. It’s a great setting for what is shaping up to be another memorable gathering for our tree care community.

The first presentations and workshops have been announced, previewing a programme that reflects both the depth of expertise within our profession and the pressing issues facing the industry today. The emerging themes, drawn from a fantastic response to our call for abstracts, highlight the latest innovations and evolving roles for arboriculturists in a changing world.

Conference is renowned for a welcoming atmosphere and networking opportunities, where you’ll enjoy the best presentations, workshops and socials in the 2026 arboricultural calendar. Whether you’re a longstanding attendee or have never joined in before, we look forward to seeing you there.

Programme preview

Presenters, content and timings can be subject to change. See online for further programme announcements.

A toxic afterlife: Trees and the dead

Alex Needs

Humans have always sought meaningful ways to return to the earth. From the hanging coffins of the Philippines and Tibetan sky burials to the sacred, untouched groves of ancient India and traditional Islamic and Jewish shroud burials, diverse cultures have long embraced a natural return to the elements.

Today, a surging ‘green burial’ movement seeks to revive these nature-connected traditions. However, as arboriculturists, we face a hidden conflict: the human desire to rest beneath a beautiful, mature tree can sometimes kill the very canopy we seek to preserve. Modern conventional burials routinely introduce highly toxic embalming fluids, such as formaldehyde, and non-biodegradable vaults directly into critical root zones. Cremation – often mistakenly viewed as an eco-friendly alternative – produces ashes that are surprisingly harmful to vegetation. Human cremains have an extreme pH of up to 11.8 and sodium levels 2,000 times higher than plants can naturally tolerate. When scattered heavily around a tree, these ashes block essential nutrient uptake and damage delicate root systems.

This presentation explores how we can bridge the gap between honouring the dead and protecting tree health. Alex will journey through historical cultural practices that naturally benefit the soil, contrasting them with the hazards of modern interment. He will share accessible, practical arboricultural methods to mitigate these risks and outline best practices such as setting safe excavation distances based on trunk diameter, utilising hand-digging protocols, positioning graves radially to prevent lateral root severance, and applying specialised soil amendments to neutralise the toxicity of cremains before scattering. By blending global cultural wisdom with modern tree care, we can ensure that our memorial landscapes remain thriving, living ecosystems for generations to come.

Alex Needs, Director of Holt Arboriculture, is a Chartered Arboriculturist and Arboricultural Association Registered Consultant with over 20 years of experience. His career spans roles from climbing arborist to senior tree officer in the public sector and principal consultant in the private sector. Alex specialises in tree safety, planning and expert witness services. He is a trustee for Fund4Trees and contributed to the National Tree Safety Group’s industry guidance.

Tree equity, benefits and maintenance in Stirling

Carla Padilla Salas

Trees are good for neighbourhoods – they provide shade, help with stormwater and make places feel more liveable. But not everyone gets the same benefits. This study takes a closer look at Stirling, comparing neighbourhoods that score high on the Tree Equity Score with those that score low. The goal is to go beyond simply counting how many trees there are. Instead, the focus is on understanding what is actually happening with the ecosystem services those trees provide and, importantly, how they are being maintained.

The research focuses on two main aspects. First, the benefits trees offer – for example, cooling the area, absorbing carbon and managing rainwater. Second, the maintenance they receive. Are trees getting regular pruning and care, or are they mostly dealt with only when they become a problem? It is expected that in neighbourhoods with higher tree equity, trees are healthier, better cared for and provide more benefits. In contrast, in lower-equity areas, the expectation is to find fewer trees, more stressed or struggling trees and a pattern of maintenance that only kicks in when something goes wrong – like roots damaging a pavement or a branch becoming a hazard.

What this study tries to understand is whether this creates a cycle. If neighbourhoods with fewer resources also get less proactive tree care, their trees do not thrive and residents do not receive the same benefits. That means achieving tree equity is not just about planting more trees – it is about making sure trees in every neighbourhood get the ongoing care they need to actually grow and do their job.

Carla Padilla Salas is an ISA Certified Arborist and a master’s student in Environmental Management at the University of Stirling. Originally from Costa Rica, she has worked in environmental education and inter-urban biological corridors, experiences that have shaped her understanding of how green spaces connect communities with nature. These experiences now inform her research on urban forestry, tree equity and maintenance practices in Stirling.

Trees of the Middle East: Observations on urban ecosystems and adaptation

Mark Laurence

The modern Middle East combines rapid urban growth with extreme climate conditions. Despite this, landscapes flourish through heavy use of TSE (treated sewerage water) and imported subtropical species. This approach has been used since the 1970s, and many created landscapes are now mature. However, horticulture is rarely recognised as a discipline, arboriculture is only emerging, and maintenance practices remain largely traditional and often inappropriate.

Climate change is intensifying heat, storms and heavy rainfall, with summer temperatures in the UAE often exceeding 50°C. Trees grown with irrigation and limited root space are therefore prone to windthrow and damage, but culturing the landscape as an urban ecosystem could enhance resilience.

Mark’s observations draw on 15 years spent working as an arboricultural consultant in the region, including visits to brownfield sites where many introduced species, left unmanaged, are forming novel (or hybrid) ecosystems without irrigation or intervention. Native trees are often absent from these sites, while many so-called ‘invasive’ ornamental species thrive. Their success suggests a new model for unirrigated, resilient landscapes that function as adapted ecosystems – providing shade, urban heat mitigation, stormwater retention, living soils and even urban productive systems for food or coppicing for mulch production.

Recognising trees as keystone elements of the urban ecosystem – and adopting ecological arboriculture – will play a crucial role in fostering a transformation to environmentally attuned, climate adapted and people-friendly landscapes.

Mark Laurence is a consulting arboriculturist (ISA certified) and landscape designer, working with sustainability and ecological principles. For the past 15 years he has been consulting in the Middle East (but based in the UK) on trees in park redevelopments, palaces and commercial projects. He has carried out site surveys, led staff training on basic pruning techniques and organised tree operations on historical sites. Mark was a climbing arborist during the 1980s.

Creating bat roosts in trees

Sean Shereston and Jim Mullholland

Fourteen of the UK’s 18 bat species live in trees, with some species spending all year in them. Due to their complex ecology, a colony of tree-roosting bats may use up to 50 trees across the year. However, tree habitats don’t last forever; trees or their features eventually fall. The longevity of tree-dwelling bats, therefore, requires a constant supply of new roost sites.

Historically, options for tree roost mitigation have been limited to bat boxes and habitat translocation. However, these are short-term fixes and not without limitations. 

Can targeted damage to trees provide an alternative solution to this problem? 

Sean Shereston (Director, Arbology) is an arborist and bat ecologist who builds tools and techniques that push survey practice forward – spanning software, optics, drones and canopy access.

Jim Mullholland (Director, BATS Research & Training) is an ecologist and arborist specialising in bats and veteran trees.

Crown restoration of heavily mutilated urban trees as an alternative to replacement planting

Ioan Stetca

Veteran urban trees are rapidly declining across many Romanian cities, a trend largely driven by repeated cycles of severe pruning and crown mutilation. When these trees eventually deteriorate, the default response is removal and replacement – yet this approach overlooks a fundamental ecological reality: no newly planted tree can immediately replicate the habitat complexity, microclimate regulation or ecosystem services provided by a mature specimen.

This presentation will explore practical and evidence-informed strategies for the restoration of heavily damaged urban tree crowns, situating them within a broader framework of urban biodiversity conservation. Mature and veteran trees serve as irreplaceable ecological anchors – supporting populations of cavity-nesting birds, saproxylic beetles, lichens, fungi and a wide range of other organisms that depend entirely on the structural complexity found only in older trees. Once lost, this habitat continuity cannot be rapidly re-established through replacement planting alone, regardless of species selection or aftercare investment.

Drawing on field examples from Romanian urban landscapes, the presentation will demonstrate how crown restoration – where biologically justified and structurally feasible – can meaningfully extend the functional lifespan of compromised trees. Key considerations include assessing residual vigour, identifying appropriate pruning interventions to redistribute growth and integrating supplementary habitat features where natural decay processes have been interrupted.

The presentation will also challenge prevailing tree management cultures that default to removal, advocating instead for ecologically informed decision-making frameworks that weigh the long-term biodiversity value of retention against the short-term appeal of replacement. Arboricultural practitioners, urban foresters and municipal decision-makers are encouraged to reconsider the ecological cost of losing mature trees, and to recognise crown restoration as a legitimate, valuable tool within the urban tree management toolkit.

Ioan Stetca is President of the Romanian Arboricultural Association (ARA) and the founder of REwildSCAPE – a landscape design atelier. His work sits at the intersection of deep ecological understanding and high-end landscape craftsmanship, bringing scientific insight and cultural heritage together in poetic, regenerative landscapes. Ioan has degrees in forestry engineering from Transylvania University and ecology from the University of Bucharest, complemented by postgraduate studies in primeval beech forests at Wageningen University. He is also an ISA certified arborist.

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