Communicating Risk and Response of Invasive Tree Pests in Urban Forests: A Need for Context in Contemporary Media

Informing residents on detections of invasive tree pests can contribute to timely awareness, collaborative community stewardship, and increased public trust in the management of urban forest risks. These updates are typically brief with news stories distilling complex ecological and management realities into simplified narratives.

While contemporary media enables rapid access to information, the format of the medium itself can narrow and inadvertently shape perceptions of invasive tree pest risk and response within the context of long-term urban forest resilience and sustainability.

The sections that follow examine the implications of limited context in contemporary media narratives about invasive tree species and their management while proposing strengthened partnerships as an essential strategy in meeting escalating climatic, ecological, social, and infrastructural challenges that increasingly jeopardize the long-term sustainability of urban forests.

Quiet Storms Beneath the Bark

One challenge associated with supporting public understanding of invasive species detections is promoting awareness that long periods without detections does not necessarily mean diminished risk.

Understanding more about Dutch elm disease (DED) and how it infects and kills elm trees can help. DED is a fungus that clogs internal water-transporting vessels (xylem) and leads to the death of the infected tree. Further spread of this fungus to other trees occurs underground through complex root systems and containment of DED requires removal of nearby elm trees.

Until symptoms of an infection are outwardly observed, the absence of DED could be assumed. Some might think, ‘if a tree looks healthy, then it probably is, right?’ This is not necessarily the case. As long as the fungi that cause Dutch elm disease, Ophiostoma ulmi and Ophiostoma novo-ulmi , that are carried on external body surfaces of bark beetles is present, the potential for new infections remains. This is where ongoing surveillance for DED and vigilance for the potential presence other invasive pests, as part of regular urban forest maintenance plans, is crucial. When detection occurs, it is evidence that current systems are functioning as they were designed: to catch issues as early as possible to prevent further spread and protect remaining tree inventories.

Beyond understanding the invasive ecology of these pests and ensuring surveillance efforts are maintained, how else can these trees be protected? A multi-approach is required. Equally valuable considerations include sustained investment in multidisciplinary surveillance and monitoring protocols, adaptive urban tree supply networks, innovative local field research, and community education and engagement. Historical review of invasive species management approaches have repeatedly demonstrated that no single tool is sufficient and over-reliance on singular practices leads to disastrous results.

The Ecology of Susceptibility

Understanding the risks and impacts associated with compounding environmental factors that shape urban tree health and vulnerability to invasive tree species takes time and context that short public updates are not always able to capture.

These compounding factors that provide greater context include referencing how organisms interact with each other and their environment. There are two such factors. The first, nonliving organisms (abiotic factors) essential to tree health, but often degraded in urban environments, include compromised soil structure and soil ecology, poor air quality, climate-driven weather extremes, and physical or mechanical damage. Together, these stresses reduce a tree’s capacity to thrive, weaken its defense systems, and narrow recovery windows.

The second set of factors that are important to consider for greater context include living organisms (biotic factors) that are detrimental to tree health. They are: invasive insect species, pathogens such as bacteria, viruses, and fungi, competing vegetation, and harmful human and wildlife activity.

Abiotic and biotic factors co-exist and accumulate over long periods of time. Together, they can contribute to increased susceptibility and are recognized as symptoms of a strained ecosystem. Invasive insects and pathogens are more likely to establish in stressed, weakened trees than in healthy ones. They are especially successful in cities where urban forests often rely on a limited number of widely planted species, where busy human activity accelerates their movement, where geographically fragmented green spaces create stressed ecological boundaries, and where the slow pace of tree growth, long-term planning and budget cycles are easily outpaced by rapidly spreading invasive species.

When Zero Becomes A Blind Spot

When narratives are suggestive of expectations that center on zero detections as a target to be achieve or maintained without sufficient context, it can constrain opportunities for learning and adaptation. It may also inadvertently reinforce false assumptions of predictability and control, shaping risk perception in ways that oversimplify invasive species ecology while also overlooking the inherent variability of natural systems.

A fuller context includes understanding how invasive species travel vast distances via global trade and international travel, exploit existing stresses that trees experience in urban environments, target genetic vulnerabilities in trees that do not exist in their native habitat, and spread rapidly leading to overwhelmed systems designed for stability rather than biological disruption.

It is equally valuable to consider historic urban forest design decisions and the climate context of prairie cities. Near monocultures of elm (and ash trees) planted in the early to mid-1900s are now struggling to persist in environments that differ markedly from those which they were originally established; the intersecting ecological processes and human systems surrounding them have significantly shifted.

Reflecting more deeply on these dynamics and on how risk is framed may help inform more effective invasive species management approaches moving forward. In doing so, it could lead to opportunities that inherently strengthen public literacy and sensemaking for sustained stewardship, leading to diversified capacity for progressive surveillance and management approaches.

Systems-Thinking for the Long Game

A management reality of invasive tree species is that they require sustained multi-level investment and coordinated responsive management plans to contain and slow their spread. Competing municipal and provincial priorities can lead to impaired urban forest, pest lab, and integrated pest management (IPM) programs.

An often over-looked and unrealized resource with unlimited potential for future urban forest resilience and sustainability are highly integrated, inclusive, and equitable participatory governance models. The development of this approach would bring diverse community stewards, advisors, and governing actors together to co-develop long-term protective strategies by pooling knowledge, capacity, and shared responsibility across existing systems.

Co-protection of these natural assets, viewed as essential urban infrastructure, is integral to collective quality of life and to long-term ecosystem resilience.

Urban trees are not an optional urban enhancement, they are fundamental to healthy cities. Those ecoservices that sustain life, naturally distributed within urban forest systems include air purification, carbon sequestration, temperature regulation, stormwater management, soil stabilization, and habitats for birds, mammals, and pollinators.

Trees produce the oxygen we need to breath.

Trees support mental health and wellbeing, contribute to cultural heritage and placemaking, and support a sense of safety and social cohesion. Cumulatively, they reduce energy costs, increase property values, and extend infrastructure lifespans.

As pressures on municipal systems intensify, investing in the protection of these natural assets that deliver multiple, overlapping benefits becomes increasingly difficult to overlook.

A Pathway Toward Resilient Canopies

Community-led initiatives within collaborative governance models are characteristically adaptive and creative in scope and application. Knowing that DED and other invasive insects spread without regard for jurisdictional, ecological, and social boundaries, the risk that spread and establishment represents in terms of scale of impact highlights the need for broad collaboration. With respect to invasive tree species, citizen science projects have demonstrated success in complimenting and extending early detection and monitoring efforts, thereby slowing their spread.

Participatory urban forest governance models reflect and uphold unique cultures, recognize lived experience and place-based knowledge, develop stronger social cohesion and shared ownership of public spaces, generate new learning and awareness, provide proactive support for ecosystem recovery and continuity, and affirm more equitable participation in the shaping of local environments.

When Loss Leads

Deliberate learning from jurisdictions that have experienced the devastating losses of their urban forests to invasive tree species such as DED and EAB can help normalize their presence without minimizing the seriousness of their impacts on local ecosystems and ecoservices. This proactive perspective-setting can guide public concern toward more meaningful and sustained acts of tree stewardship.

This framing invites us all to see trees beyond the blurring effects experienced from our vehicles, bikes, and busy-ness of our lives. To see trees as the living organisms that they are and in doing so, communicates the timely need for shared responsibility and renewed investment in their long-term care.

By providing context around how and why invasive species affect the trees nearest to us, we can better understand how these impacts shape daily urban experiences and overall quality of life.

This approach makes it more likely we will champion for their protection.