Urban Tree Canopy for Water Quality Control & Storm-water Absorption
Summary
Through the Neat Streets' Million Trees Miami Initiative, Miami-Dade County has committed to planting 1 million trees (amounting to 30% tree canopy coverage), as a means of mitigating flooding and water quality issues (as well as various other environmental and hydrological issues) and achieving a healthy, urban environment.
Miami-Dade County (MDC) is one of the United States of America's most vulnerable areas to climate change. The city of Miami already faces frequent flooding, has difficulties managing excess storm-water runoff, and faces pollution of its water supply due to a number of factors (e.g. porous limestone aquifers that are close to the surface, saltwater intrusion, presence of Superfund sites, septic tanks and a rising groundwater table) (Caccia & Boyer, 2005; Renken et al., 2005). Furthermore, the majority of current climate models predict that, much like other coastal cities, Miami will likely face exacerbated rainstorms, flooding, and sea level rise due to the effects of the changing climate (Hallegatte et al., 2013; Keenan, Hill & Gumber, 2018). Although chronic inundation by seawater as well as property losses are typically discussed in regard to the dangers that climate change poses to the City of Miami, water quality issues are also a primary concern (Pant & Cha, 2018).
As flooding and storms get worse, unexpected movement of surface water can push toxins (from Superfund sites, septic tanks, non-point sources, etc.) into the city's pollution-prone aquifers, thereby contaminating MDC's groundwater supply (US EPA, 2014). Without proper protection of its limestone aquifers, Miami-Dade County faces serious water quality concerns which could result in water insecurity for the city. More generally, Miami faces issues related to climate change that are similar to those in other urban areas, including rising temperatures, high energy (i.e. cooling) costs, and pollution.
Intervention
As a means of enhancing the overall quality of life in the city and combating the negative effects of climate change (in particular, water quality issues caused by excess storm-water runoff and the urban heat island effect), Miami-Dade County has committed to increasing its urban tree canopy coverage through the Million Trees Miami Initiative. The initiative was designed and implemented by Neat Streets Miami, a Miami-Dade County Board under the jurisdiction of the Miami-Dade County Parks, Recreation and Open Spaces Department (PROS). Although Neat Streets is a government initiative which receives funding from Miami-Dade County, it functions much like a non-profit, partnering with charities and private sector businesses (both locally and nationally), to further its tree planting efforts (Henseler, 2020). In the past, tree planting has occurred in partnership with private sector companies like Bacardi, Coca Cola, FedEx and Verizon, as well as NGOs like One Tree Planted and American Forests (Our Neighborhoods, 2018; Henseler, 2020).
One of the primary reasons the county committed to the Million Trees initiative is Miami's vulnerability to the effects of climate change, including pollution of aquifers caused by exacerbated flooding (Pant & Cha, 2018; US EPA, 2014). Trees serve as natural storm-water retention and filtration systems, helping to stabilize the hydrological cycle and prevent aquifer contamination through nutrient uptake from storm-water runoff ( Livesley, McPherson & Calfapietra, 2016).
Neat Streets' Million Trees Miami initiative is an ongoing effort to plant 1 million trees across MDC, amounting to an urban tree canopy coverage of 30%. The targets are as follows: 50% tree canopy in suburban residential areas, 25% tree canopy in urban residential areas and 10% tree canopy in the urban core. Miami-Dade County has committed to planting 30% of the 1 million (a total of 300,000 trees), while the remaining 700,000 trees are to be planted in partnership with municipalities, schools, universities, institutions, corporations and private citizens (MDC Department of Parks, Recreation and Open Spaces). Neat Streets' initiative engages in tree-planting events and encourages groups and individuals to plant native or Florida-friendly trees on streets and corridors through its Tree Matching Grant Program, which gives special preference to low-canopy coverage and underserved areas (Our Neighborhoods, 2018). The initiative also undertakes tree planting in partnership with private sector companies and NGOs, typically through employee stewardship programs, in which employees volunteer to plant trees across the county. Since Hurricane Irma struck in 2017 and uprooted many of the trees planted, the Arbor Day Foundation has partnered with Neat Streets Miami to restore tree coverage in areas particularly hard-hit by the storm. Through the partnership, Million Trees Miami gives away between 500 and 1,000 trees a couple of times per year (Our Neighborhoods, 2018). MDC keeps track of the initiative's progress by regularly updating its assessment of tree canopy coverage via satellite imaging.
Challenges
The Million Trees Miami Initiative faces several challenges, including storm damage from hurricanes, which can uproot trees and hinder canopy stability. Water quality and pollution risks remain a concern, as trees may not fully address contamination from Superfund sites and septic tanks. Securing consistent funding and equitable tree distribution across all areas, especially underserved neighborhoods, is also difficult. Additionally, maintaining long-term tree health and engagement from local communities requires ongoing resources and effort.
Outcomes
The Million Trees Miami initiative is active. In 2016, MDC's Urban Tree Canopy Assessment placed the county's canopy coverage at nearly 20%, but it is estimated that up to 30% of that coverage may have been uprooted and lost in the past 4 years due to hurricane damage (Henseler, 2020). Since then, the initiative has redefined its goal from planting 1 million trees to planting as many trees as possible, to ensure the longevity of the urban canopy in the face of storms and other potentially destructive events (Henseler, 2020).
From 2011 to 2016, Miami-Dade County achieved 19.9% urban tree canopy coverage, meaning that, through Neat Streets' initiative and partnerships, 660,000 trees were planted throughout the county in the 5-year period. From 2018 to 2019, Million Trees planted 1,446 trees throughout MDC and gave away another 4,095. Finally, over 6,500 trees were planted in the county in a 1-year period, 1,000 trees of which were planted specifically through the Million Trees' Street Tree Matching Grant program (Henseler, 2020). Overall, the initiative has yielded many positive outcomes, including aiding in storm-water retention for a more resilient hydrological cycle, as well as mitigating pollution to Miami's aquifers by nutrient uptake through the trees' root systems. In addition to these effects, the Million Trees Miami initiative has produced a cooling effect in various parts of the city, fostered adaptation to climate change by mitigating some of its deleterious effects, aided in CO2 sequestration and produced a number of positive social, health, and economic benefits.
The Million Trees Miami initiative led to other tree planting initiatives in the city, including Growing Green Playgrounds and Growing Green Bus Stops. These initiatives targeted unsafe conditions and surface temperatures by planting shading trees in playgrounds and at bus stops across the city, respectively (Our Neighborhoods, 2018). In addition, this led to widespread use of the #Tree05 social media hashtag as a communications tool, in order to engage Miami residents and visitors in the Million Trees Miami urban tree coverage campaign (Our Neighborhoods, 2018; MDC Department of Parks, Recreation and Open Spaces, 2019).
References
Urban Tree Canopy for Water Quality Control & Storm-water Absorption
Summary
Through the Neat Streets' Million Trees Miami Initiative, Miami-Dade County has committed to planting 1 million trees (amounting to 30% tree canopy coverage), as a means of mitigating flooding and water quality issues (as well as various other environmental and hydrological issues) and achieving a healthy, urban environment.
Miami-Dade County (MDC) is one of the United States of America's most vulnerable areas to climate change. The city of Miami already faces frequent flooding, has difficulties managing excess storm-water runoff, and faces pollution of its water supply due to a number of factors (e.g. porous limestone aquifers that are close to the surface, saltwater intrusion, presence of Superfund sites, septic tanks and a rising groundwater table) (Caccia & Boyer, 2005; Renken et al., 2005). Furthermore, the majority of current climate models predict that, much like other coastal cities, Miami will likely face exacerbated rainstorms, flooding, and sea level rise due to the effects of the changing climate (Hallegatte et al., 2013; Keenan, Hill & Gumber, 2018). Although chronic inundation by seawater as well as property losses are typically discussed in regard to the dangers that climate change poses to the City of Miami, water quality issues are also a primary concern (Pant & Cha, 2018).
As flooding and storms get worse, unexpected movement of surface water can push toxins (from Superfund sites, septic tanks, non-point sources, etc.) into the city's pollution-prone aquifers, thereby contaminating MDC's groundwater supply (US EPA, 2014). Without proper protection of its limestone aquifers, Miami-Dade County faces serious water quality concerns which could result in water insecurity for the city. More generally, Miami faces issues related to climate change that are similar to those in other urban areas, including rising temperatures, high energy (i.e. cooling) costs, and pollution.
Issue
Intervention
As a means of enhancing the overall quality of life in the city and combating the negative effects of climate change (in particular, water quality issues caused by excess storm-water runoff and the urban heat island effect), Miami-Dade County has committed to increasing its urban tree canopy coverage through the Million Trees Miami Initiative. The initiative was designed and implemented by Neat Streets Miami, a Miami-Dade County Board under the jurisdiction of the Miami-Dade County Parks, Recreation and Open Spaces Department (PROS). Although Neat Streets is a government initiative which receives funding from Miami-Dade County, it functions much like a non-profit, partnering with charities and private sector businesses (both locally and nationally), to further its tree planting efforts (Henseler, 2020). In the past, tree planting has occurred in partnership with private sector companies like Bacardi, Coca Cola, FedEx and Verizon, as well as NGOs like One Tree Planted and American Forests (Our Neighborhoods, 2018; Henseler, 2020).
One of the primary reasons the county committed to the Million Trees initiative is Miami's vulnerability to the effects of climate change, including pollution of aquifers caused by exacerbated flooding (Pant & Cha, 2018; US EPA, 2014). Trees serve as natural storm-water retention and filtration systems, helping to stabilize the hydrological cycle and prevent aquifer contamination through nutrient uptake from storm-water runoff ( Livesley, McPherson & Calfapietra, 2016).
Neat Streets' Million Trees Miami initiative is an ongoing effort to plant 1 million trees across MDC, amounting to an urban tree canopy coverage of 30%. The targets are as follows: 50% tree canopy in suburban residential areas, 25% tree canopy in urban residential areas and 10% tree canopy in the urban core. Miami-Dade County has committed to planting 30% of the 1 million (a total of 300,000 trees), while the remaining 700,000 trees are to be planted in partnership with municipalities, schools, universities, institutions, corporations and private citizens (MDC Department of Parks, Recreation and Open Spaces). Neat Streets' initiative engages in tree-planting events and encourages groups and individuals to plant native or Florida-friendly trees on streets and corridors through its Tree Matching Grant Program, which gives special preference to low-canopy coverage and underserved areas (Our Neighborhoods, 2018). The initiative also undertakes tree planting in partnership with private sector companies and NGOs, typically through employee stewardship programs, in which employees volunteer to plant trees across the county. Since Hurricane Irma struck in 2017 and uprooted many of the trees planted, the Arbor Day Foundation has partnered with Neat Streets Miami to restore tree coverage in areas particularly hard-hit by the storm. Through the partnership, Million Trees Miami gives away between 500 and 1,000 trees a couple of times per year (Our Neighborhoods, 2018). MDC keeps track of the initiative's progress by regularly updating its assessment of tree canopy coverage via satellite imaging.
Challenges
The Million Trees Miami Initiative faces several challenges, including storm damage from hurricanes, which can uproot trees and hinder canopy stability. Water quality and pollution risks remain a concern, as trees may not fully address contamination from Superfund sites and septic tanks. Securing consistent funding and equitable tree distribution across all areas, especially underserved neighborhoods, is also difficult. Additionally, maintaining long-term tree health and engagement from local communities requires ongoing resources and effort.
Outcomes
The Million Trees Miami initiative is active. In 2016, MDC's Urban Tree Canopy Assessment placed the county's canopy coverage at nearly 20%, but it is estimated that up to 30% of that coverage may have been uprooted and lost in the past 4 years due to hurricane damage (Henseler, 2020). Since then, the initiative has redefined its goal from planting 1 million trees to planting as many trees as possible, to ensure the longevity of the urban canopy in the face of storms and other potentially destructive events (Henseler, 2020).
From 2011 to 2016, Miami-Dade County achieved 19.9% urban tree canopy coverage, meaning that, through Neat Streets' initiative and partnerships, 660,000 trees were planted throughout the county in the 5-year period. From 2018 to 2019, Million Trees planted 1,446 trees throughout MDC and gave away another 4,095. Finally, over 6,500 trees were planted in the county in a 1-year period, 1,000 trees of which were planted specifically through the Million Trees' Street Tree Matching Grant program (Henseler, 2020). Overall, the initiative has yielded many positive outcomes, including aiding in storm-water retention for a more resilient hydrological cycle, as well as mitigating pollution to Miami's aquifers by nutrient uptake through the trees' root systems. In addition to these effects, the Million Trees Miami initiative has produced a cooling effect in various parts of the city, fostered adaptation to climate change by mitigating some of its deleterious effects, aided in CO2 sequestration and produced a number of positive social, health, and economic benefits.
The Million Trees Miami initiative led to other tree planting initiatives in the city, including Growing Green Playgrounds and Growing Green Bus Stops. These initiatives targeted unsafe conditions and surface temperatures by planting shading trees in playgrounds and at bus stops across the city, respectively (Our Neighborhoods, 2018). In addition, this led to widespread use of the #Tree05 social media hashtag as a communications tool, in order to engage Miami residents and visitors in the Million Trees Miami urban tree coverage campaign (Our Neighborhoods, 2018; MDC Department of Parks, Recreation and Open Spaces, 2019).
Issues |
|---|
Climate Change and Water |
Solutions |
|---|
Sustainable Water Supply & Climate Solutions |
References
Caccia, V. G., & Boyer, J. N. (2005). Spatial patterning of water quality in Biscayne Bay, Florida as a function of land use and water management. Marine Pollution Bulletin, 50(11), 1416-1429.
Escobedo, F., Varela, S., Zhao, M., Wagner, J. E., & Zipperer, W. (2010). Analyzing the efficacy of subtropical urban forests in offsetting carbon emissions from cities. environmental science & policy, 13(5), 362-372.
Hallegatte, S., Green, C., Nicholls, R. J., & Corfee-Morlot, J. (2013). Future flood losses in major coastal cities. Nature climate change, 3(9), 802-806.
Henseler, K. (2020, July 1). Million Trees Plans Pruned. Miami Today. Retrieved July 23, 2020, from https://www.miamitodaynews.com/2020/07/01/million-trees-plans-pruned/
Keenan, J. M., Hill, T., & Gumber, A. (2018). Climate gentrification: from theory to empiricism in Miami-Dade County, Florida. Environmental Research Letters, 13(5), 054001.
Livesley, S. J., McPherson, E. G., & Calfapietra, C. (2016). The urban forest and ecosystem services: impacts on urban water, heat, and pollution cycles at the tree, street, and city scale. Journal of environmental quality, 45(1), 119-124.
Miami-Dade County Department Parks, Recreation and Open Spaces. (n.d.). Getting to a Million Trees. Retrieved July 23, 2020, from https://www8.miamidade.gov/global/recreation/milliontrees/getting-to-a-million-trees.page
Miami-Dade County Department of Parks, Recreation and Open Spaces, Neat Streets Miami. (2019, November 3). Media Release Guidelines: Neat Streets Miami/Million Trees Miami [Press release]. Retrieved July 23, 2020, from https://www.miamidade.gov/parks/library/media-release-guidelines.pdf
Million Trees Miami Wants To Rebuild Our Community's Tree Canopy. What Exactly Does That Mean? (2018, May 08). Retrieved July 23, 2020, from https://ourneighborhoods.com/million-trees-miami-wants-rebuild-communitys-tree-canopy-exactly-mean/
Pant, S., & Cha, E. J. (2018). Effect of climate change on hurricane damage and loss for residential buildings in Miami-Dade County. Journal of Structural Engineering, 144(6), 04018057.
Renken, R. A., Cunningham, K. J., Zygnerski, M. R., Wacker, M. A., Shapiro, A. M., Harvey, R. W., ... & Ryan, J. N. (2005). Assessing the vulnerability of a municipal well field to contamination in a karst aquifer. Environmental & Engineering Geoscience, 11(4), 319-331.
Roy, S., Byrne, J., & Pickering, C. (2012). A systematic quantitative review of urban tree benefits, costs, and assessment methods across cities in different climatic zones. Urban Forestry & Urban Greening, 11(4), 351-363.
Ulmer, J. M., Wolf, K. L., Backman, D. R., Tretheway, R. L., Blain, C. J., O’Neil-Dunne, J. P., & Frank, L. D. (2016). Multiple health benefits of urban tree canopy: The mounting evidence for a green prescription. Health & Place, 42, 54-62.
U.S. Environmental Protection Agency. (2014). Climate Change Adaptation Plan (Rep. No. EPA 100-K-14-001). doi:https://www.epa.gov/sites/production/files/2016-08/documents/epa-climate-change-adaptation-plan.pdf