Hedonic Analysis of Forest Pest Invasion: the Case of Emerald Ash Borer

Abstract

The emerald ash borer (EAB) was first detected in North America in 2002, and since its introduction, this invasive pest has killed millions of ash trees. While EAB kills native North American ash trees in all settings, its impacts have been especially large in urban areas where ash has been a dominant street tree, especially in residential areas. While some management costs, such as insecticide treatment, tree removal, or tree replacement, are relatively straightforward to compute, the impact that EAB has had on residential property values is less clear. To better understand the economic cost of EAB in urban settings, we conducted a hedonic property value analysis to evaluate the impact of ash tree damages due to EAB infestation on housing sales prices. This study was conducted in the city of Milwaukee, Wisconsin, which had high stocking levels of ash trees prior to EAB’s arrival. The objectives of the study are to investigate: (1) how EAB-infested ash trees affect property values; (2) whether the benefits from healthy ash trees to property value change after arrival of EAB; and (3) whether healthy ash trees located within infested neighborhoods provide the same benefits as the healthy ash trees located outside of infested neighborhoods. In general, our results show that the EAB outbreak has had a negative impact on home values for properties located in close proximity to the ash tree component of the urban forest. This result holds true for neighborhoods where EAB does not yet pose an imminent threat, and is amplified for neighborhoods where EAB has been detected. Our results highlight the early stages of a dynamic economic process that impacts urban residential property owners subject to the risk of EAB or other tree pests and diseases. In general, we find that forward-looking behavior of residential property owners is capitalized into property values during the process of forest pest infestation.

Understanding Tree Health under Increasing Climate and Trade Challenges: Social System Considerations

“…In this context, there is a legitimate policy concern that the risks associated with OPM may negatively impact the future of oak trees in the urban landscape, such that land managers may be tempted to remove existing infested oak trees that potentially pose a risk to human health or simply refuse to plant new oak. Similar to Ambrose-Oji et al [7] and Li et al, [6] there is a risk that the iconic oak tree may be seen as a liability. Marzano et al [11] investigate how land managers assess the tradeoffs between the perceived risks of OPM, the management measures used to control the pest and the values associated with oak trees and the biodiversity they support.…”

“…They also found that such reductions in forest quality resulted in a reduction in property values in affected areas. Li et al [6] made similar observations in the context of the negative impact of tree damage due to emerald ash borer (Agrilus planipennis) (EAB) on home values in urban neighbourhoods with a high ash component in Milwaukee, Wisconsin, USA. Indeed, several of the papers from the UK and USA focus on ash, reflecting wide-ranging concerns around the loss of this prevalent and often culturally important species.…”

“…Emerald ash borer in the USA and ash dieback (Hymenoscyphus fraxineus) in the UK have had devastating consequences for people and places where it has occurred and it is still spreading. In the USA, Li et al [6] emphasise that tree boring pests such as EAB can severely impact social and economic values. For example, extensive tree mortality due to EAB can lead to a significant reduction in the ecosystem services those trees provide such as shade, privacy, regulating water quality and visual aesthetics, and this loss will have a knock-on effect on property values [6].…”

“…In the USA, Li et al [6] emphasise that tree boring pests such as EAB can severely impact social and economic values. For example, extensive tree mortality due to EAB can lead to a significant reduction in the ecosystem services those trees provide such as shade, privacy, regulating water quality and visual aesthetics, and this loss will have a knock-on effect on property values [6]. Tree and plant health in urban settings is an under-researched area even though impacts on ecosystem services are likely to be greatest.…”

“…In the UK, for example, decisions about ash dieback at the local authority level can take place separately across multiple departments, depending on where the ash trees are located. A concern raised both by Ambrose-Oji et al [7] and Li et al [6] in circumstances where the likelihood of pest or pathogen impacts are high, but there are uncertainties about what to do is that trees can be seen as a threat or liability rather than an asset. Thus, understanding knowledge (e.g., about pests and diseases), values (e.g., associated with trees) and risk perceptions are likely to be important and key areas where the social sciences can contribute.…”