Geoffrey H. Donovan

Urban trees and the risk of poor birth outcomes

This paper investigated whether greater tree-canopy cover is associated with reduced risk of poor birth outcomes in Portland, Oregon. Residential addresses were geocoded and linked to classified-aerial imagery to calculate tree-canopy cover in 50, 100, and 200 m buffers around each home in our sample (n=5696). Detailed data on maternal characteristics and additional neighborhood variables were obtained from birth certificates and tax records. We found that a 10% increase in tree-canopy cover within 50 m of a house reduced the number of small for gestational age births by 1.42 per 1000 births (95% CI-0.11-2.72). Results suggest that the natural environment may affect pregnancy outcomes and should be evaluated in future research.

The Effect of Trees on Crime in Portland, Oregon

The authors estimate the relationship between trees and three crime aggregates (all crime, violent crime, and property crime) and two individual crimes (burglary and vandalism) in Portland, Oregon. During the study period (2005-2007), 431 crimes were reported at the 2,813 single-family homes in our sample. In general, the authors find that trees in the public right of way are associated with lower crime rates. The relationship between crime and trees on a house’s lot is mixed. Smaller, view-obstructing trees are associated with increased crime, whereas larger trees are associated with reduced crime. The authors speculate that trees may reduce crime by signaling to potential criminals that a house is better cared for and, therefore, subject to more effective authority than a comparable house with fewer trees.

Wildfire risk and housing prices: a case study from colorado springs

In 2000, concerned about the risks of wildfires to local homes, the Colorado Springs Fire Department rated the wildfire risk of 35,000 housing parcels within the wildland-urban interface and made its findings available online. We examine the effectiveness of this rating project by comparing the relationship between home price and wildfire risk before and after the information was posted on the Web site. Before the information was available, home price and wildfire risk were positively correlated, whereas, afterwards, they were not. (JEL R26, Q51)

Be careful what you wish for: the legacy of Smokey Bear

A century of wildfire suppression in the United States has led to increased fuel loading and large-scale ecological change across some of the nations forests. Land management agencies have responded by increasing the use of prescribed fire and thinning. However, given the continued emphasis on fire suppression, current levels of funding for such fuel management practices are unlikely to maintain the status quo, let alone reverse the effects of fire exclusion. We suggest an alternative approach to wildfire management, one that places less emphasis on suppression and instead encourages managers to balance short-term wildfire damages against the long-term consequences of fire exclusion. However, any major change in wildfire management, such as the one proposed here, will shift the costs and benefits of wildfire management, inevitably raising opposition.

The economic cost of adverse health effects from wildfire-smoke exposure: a review

The economic costs of adverse health effects associated with exposure to wildfire smoke should be given serious consideration in determining the optimal wildfire management policy. Unfortunately, the literature in this research area is thin. In an effort to better understand the nature of these economic costs, we review and synthesise the relevant literature in three areas: studies that estimated the health-related economic costs of wildfire-smoke exposure; epidemiology studies related to the health risk of wildfire smoke; and general economic studies that estimated the monetary value of preventing the specific adverse health outcomes. Based on the findings from this literature review, we identify the need for a better understanding of the effect of wildfire smoke on major and minor adverse health outcomes. It would also be useful to know more about averting behaviours among residents exposed to smoke during a wildfire event. Finally, we suggest investigating the unique health effects of wildfire smoke compared with conventional air pollution to determine whether it is appropriate to extrapolate from previously estimated conventional pollution dose-response functions.

Living in a tinderbox: wildfire risk perceptions and mitigating behaviours

The loss of homes to wildfires is an important issue in the USA and other countries. Yet many homeowners living in fire-prone areas do not undertake mitigating actions, such as clearing vegetation, to decrease the risk of losing their home. To better understand the complexity of wildfire risk-mitigation decisions and the role of perceived risk, we conducted a survey of homeowners in a fire-prone area of the front range of the Rocky Mountains in Colorado. We examine the relationship between perceived wildfire risk ratings and risk-mitigating behaviours in two ways. First, we model wildfire risk-mitigation behaviours as a function of perceived risk. Then, we model wildfire risk-mitigation behaviours and perceived risk simultaneously. The results of the simultaneous model suggest that perceived risk and wildfire risk-mitigating behaviours are jointly determined. By correctly specifying the relationship between risk perceptions and mitigating behaviours, we are better able to understand the relationship between other factors, such as exposure to a wildfire-mitigation program and wildfire risk-mitigating behaviours. We also find that having a wood roof, as well as homeowner age, income and previous experience with living in a fire-prone area, are associated with wildfire risk-mitigating behaviours.

The Effect of Newspaper Coverage and Political Pressure on Wildfire Suppression Costs

Controlling wildfire suppression expenditures has become a major public policy concern in the United States. However, most policy remedies have focused on the biophysical determinants of suppression costs: fuel loads and weather, for example. We show that two non-biophysical variables—newspaper coverage and political pressure—have a significant effect on wildfire suppression costs. Hausman tests showed that newspaper coverage and fire size were endogenous, so regression models were estimated using two-stage least squares. We suggest a number of non-biophysical policy remedies that may be able to reduce wildfire suppression expenditures more cost-effectively than traditional biophysical remedies such as fuel management.

Classrooms With Nature Views Evidence of Differing Student Perceptions and Behaviors

Viewing peaceful natural environments has been shown to restore cognitive abilities and reduce physiological arousal. As such, visual access to the natural environment is becoming more commonplace in built environments. One exception to that trend is in educational settings where windowless classrooms are used to reduce outside distractions. The current study examines differences across multiple sections of a college writing course in two types of identically designed classrooms—those with a view of a natural setting and those with a view of a concrete retaining wall. Results showed that students in the natural view classrooms were generally more positive when rating the course. Students in the natural view condition also had higher end of semester grades, but no differences in attendance were observed between conditions. Such findings suggest that classrooms with natural views offer advantages and also suggest that the inclusion of natural elements in courses could facilitate positive perceptions and better grades.

Is tree loss associated with cardiovascular-disease risk in the Women's Health Initiative? A natural experiment.

Data from the Womens Health Initiative were used to quantify the relationship between the loss of trees to an invasive forest pest-the emerald ash borer-and cardiovascular disease. We estimated a semi-parametric Cox proportional hazards model of time to cardiovascular disease, adjusting for confounders. We defined the incidence of cardiovascular disease as acute myocardial infarction requiring overnight hospitalization, silent MI determined from serial electrocardiograms, ischemic or hemorrhagic stroke, or death from coronary heart disease. Women living in a county infested with emerald ash borer had an increased risk of cardiovascular disease (HR=1.25, 95% CI: 1.20-1.31).

Conserving biodiversity using risk management: hoax or hope.

Biodiversity has been called a form of ecosystem insurance. According to the “insurance hypothesis”, the presence of many species protects against system decline, because builtin redundancies guarantee that some species will maintain key functions even if others fail. The hypothesis might have merit, but calling it “insurance” promotes an ambiguous understanding of risk management strategies and underlying theories of risk. Instead, such redundancy suggests a strategy of diversification. A clearer understanding of risk includes comprehending the important distinction between risk assessment and risk management, acknowledging the existence of undiversifiable risk, and recognizing that risk and uncertainty are not synonymous. A better grasp of risk management will help anyone interested in assessing the merits of different biodiversity conservation strategies. At stake is the adequacy of conservation strategies for mitigating human-caused biodiversity losses.