In this paper, we focus on how the risks associated with invasive tree pests and diseases are assembled by experts and decision-makers. In recent decades there has been a dramatic increase in new tree pest and disease epidemics, which has been closely linked to globalization, trade and climate change. As with other ‘wicked problems’, expert and policy assessments of the risks are fraught with uncertainty, both in terms of the available scientific evidence, which often emerges as outbreaks unfold, and the potential impacts of the pest or disease.
The Social Amplification of Risk Framework (SARF) is often used as a theoretical tool for assessing the social, psychological, institutional and cultural processes that influence risk perceptions. However, despite the SARF authors asserting that there is no such thing as ‘true’ (absolute) risk and ‘distorted’ (socially determined) risk, the use of the framework as a communication-reception process implies that expert risk assessment, and any communication and signaling of risk that results, constitutes the ‘real’ or benchmark risk against which the public’s ‘perceived’ risk is either intensified or attenuated. This is problematic when there are high levels of uncertainty and where experts and decision-makers may disagree about the nature of the risk and its impacts.
Through semi-structured interviews with 52 experts, policy makers and high-level stakeholders, we explore how uncertainty is encountered in three tree pest and disease outbreaks: Ramorum blight (Phytophthora ramorum), ash dieback (Hymenoscyphus fraxineus and oak processionary moth (Thaumetopoea processionea). Our analysis exemplifies how experts and decision-makers are social actors, drawing on a range of information sources, social networks, heuristic devices and personal observations to construct their assessments of risk and uncertainty. Further, their attention to what they perceive as public concern may influence management responses and lead to various social, environmental and institutional ripple effects.
We conclude by suggesting that a more socially-mediated process of risk assemblage is required, especially when there are high levels of uncertainty. We also ask how far the attributions experts and decision-makers make about public concern become risk drivers with the public acting as a ‘social station of risk amplification’ influencing how decision makers assess tree health risks.