Chicago Urban Wilderness: Fortifying Chicago's Urban Forests in a Changing Climate

Project Summary

This case study describes the collaborative implementation of the Urban Forestry Climate Change Response Framework (CCRF) in the Chicago region. 

Urban forests are an important part of the functionality and livability of cities. The urban ecosystems of the Chicago Region are experiencing increases in temperature, flooding, and extreme weather events that will only escalate as the climate continues to change in the coming decades. Urban forests have the potential to reduce the urban heat island effect, control flooding, and improve air quality, thus maintaining and building strong forests is of great importance to urban communities in a shifting climate.

The Chicago region project utilized a three-phase process that featured regional ecological vulnerability assessments, local ecological and socioeconomic and organizational assessments, and finally the planning and implementation of on-the-ground adaptation projects. In general, adaptation actions selected in these locations tended to focus on increased biodiversity and restoration of natural disturbance regimes, but differences in socioeconomic capacity significantly influenced both the vulnerability and the adaptive strategies pursued.

Project background and scope

In 2014, the Chicago Region Trees Initiative and the Northern Institute of Applied Climate Science (NIACS) began a partnership to assess and prepare the Chicago region’s forests for climatic changes. This led to the design and implementation of a pilot framework to assess the vulnerability of urban forests in the Chicago region to changes in climate and to incorporate that information into on-the-ground action at ten different sites in the Chicago region. The project was the first to implement the Urban Forestry Climate Change Response Framework (CCRF). The three step process of a regional vulnerability assessment, local vulnerability assessments, and the translation of this information to on-the-ground action offers urban land managers a comprehensive and collaborative medium to better prepare their forests for climate change.

Urban forests in the Chicago region are facing several challenges that could be compounded with climate change: loss of trees to pests and diseases (most recently the emerald ash borer), increased temperatures, increased flooding and extreme weather events, and a tree-canopy percentage that is low for the Midwest. This is compounded by the fact that in many cases urban trees face increased stress from air pollution, road salt, restricted rooting conditions, and improper planting, necessitating a framework unique to urban forests.

Project Process and Implementation

The Urban Forestry CCRF embraces collaboration, and many organizations contributed to the project. The U.S. Forest Service and the Northern Institute of Applied Climate Science worked with experts from the Morton Arboretum, the Field Museum, the Chicago Botanic Garden, and county and municipal agencies for this project.. Parties contributed significant expertise on climate change, Chicago’s urban forests, project design, and adaptation strategies.

The project included a series of workshops for urban forestry professionals where they assessed the vulnerability of the forests they managed and created their own adaptation plans using a menu of peer-reviewed adaptation strategies tailored for urban forests. The workshops not only gave urban forestry professionals a chance to learn about local vulnerabilities, but also to share ideas and information with each other, thus enhancing local ties and collaboration. Building these networks for the future is important to growing a resilient urban forestry environment in the Chicago Wilderness region. Although land managers differ in adaptive capacity, the scales at which they work, and management goals, the framework provided communities an opportunity to proactively assess the threats facing forests and take informed action.

Learning Objectives

1. Urban forests face unique climate change challenges that differ from their rural counterparts
2. The vulnerability of urban forests can vary across municipalities and counties due to differences in organizational and economic capacity
3. Urban foresters are used to incorporating novel species and cultivars and thus are open to projects that may facilitate transitions to current or future conditions 

Project Outcomes

The Chicago pilot project began with a comprehensive regional vulnerability assessment of the region’s trees. The assessment determined that 15% of the evaluated species have a moderate to high vulnerability to the impacts of climate change, and most of these species are North American natives at the southern reaches of their range. About half of the species had low to low-moderate vulnerability. Although many species with low vulnerability were natives such as bur oak, a large quantity of these were non-native invasives such as European buckthorn.

Local vulnerability assessments completed by municipal foresters, parks department managers, and county forest preserver managers highlighted a range of adaptive capacities amongst communities. In general, forests in affluent areas had lower vulnerability due to high ecological, organizational, social, and economic adaptive capacity. These communities tended to have more staff on hand, larger budgets for tree planting and care, and a broader volunteer base.

In a workshop focused on developing adaptation plans, urban forest managers from the Chicago region brought a climate change lens to a variety of  real-world projects (e.g. replanting parkways, nursery stock selection, flood control on open lands). Many shared the management goals of enhanced diversity, greater resilience to storm events, and increased canopy cover. The most common climate change adaptation strategy chosen by land managers was to reduce the spread of invasive species. Among both natural and managed sites, managers favored increasing species and age diversity. Managers of urban natural areas preferred incorporating native species to increase diversity, while managers of street trees and urban parks were open to incorporating new species and genotypes from outside the area that may be adapted to future conditions.

In total, land managers working with the CCRF menu of options chose a diverse set of adaptive actions for their sites (Table 1). Both the uniqueness of their site and the adaptive capacity of the land management organization influenced the adaptation actions chosen, highlighting the need for a flexible approach to adaptation planning. In choosing their actions, managers expressed a strong desire to increase diversity and canopy cover, utilizing various strategies to achieve their specific project goals.

Learn more about what people are doing to adapt in the Chicago region

Village of Riverside, IL: Reforestation Project

Village of Hazelcrest: Open Lands Flooding Mitigation

Project challenges and lessons learned

Project challenges and lessons learned

• Know your regional and local tree composition. To know what’s vulnerable, you need to know what is there. The regional climate change assessment for the Chicago region was able to make use of data from a recent sample inventory of the region’s trees that had been completed for another project. Many individual municipalities and metropolitan areas will not have this information readily available.
• Cultivars and non-natives add uncertainty. Most urban areas have many trees that are not native to their region, including cultivars or trees native to other parts of North America or other continents. In some cases, planted species are relatively rare (or entirely absent) in nature, making it difficult to know much about their ecology or tolerance of large-scale disturbances. Little may be known about the long-term tolerance of disturbance events for newer cultivars. This diverse mix of species and cultivars means that there may be greater uncertainty in estimates of vulnerability for urban trees over their rural counterparts.
• Understand the complexity of land use and cover in urban areas. Urban areas have a mix of land use and land cover types that range from highly developed to relatively pristine, with much variation in between. Differences in topography, soils, impervious cover, economic factors, and local differences in age class and tree condition can all lead to differences in vulnerability for an urban forest. When assessing vulnerability over a large region, much of this complexity will be lost. This is why the local assessments were so critical.
• Urban foresters are always adapting. Harsh urban environments reduce the number of native species that can survive, thus spurring urban forest managers to seek out species and cultivars from outside the region in order to maintain biodiversity and canopy cover. This is especially true in highly altered, developed areas. Thus workshop participants were very open to incorporating new species and cultivars that may be adapted to current and future climate conditions. 

External Source

Brandt, L.; Scott, L.; Derby Lewis, A.; Darling, L.; Fahey R. 2016. Lessons learned from the Urban Forestry Climate Change Response Framework. Houghton, MI: Northern Institute of Applied Climate Science. 36 pp.

Related documents and resources

References

Brandt, Leslie; Derby Lewis, Abigail; Fahey, Robert; Scott, Lydia; Darling, Lindsay; Swanston, Chris 2016. A framework for adapting urban forests to climate change. Environmental Science & Policy: 10 pages.https://www.fs.usda.gov/treesearch/pubs/53036

Brandt, Leslie; Scott, Lydia; Derby Lewis, Abigail; Darling, Lindsay; Fahey, Robert. 2016. Lessons learned from the Urban Forestry Climate Change Response Framework. Houghton, MI: Northern Institute of Applied Climate Science. 36 pp. http://forestadaptation.org/node/630