From a society standpoint, we are encouraged to think about the greenhouse gas removing qualities of trees, specifically, their ability to take up a lot of carbon dioxide. Running quick numbers, 1 cubic foot of concrete results in about 150 pounds of CO2 emissions, while one mature tree can sequester up to ~50 pounds of CO2 per year. On top of that, 1 mature tree can provide a day’s supply of oxygen for up to 4 people, not to mention the benefits of shade in urban heat islands. Trees are cooler.
Trees will still get ripped out for sidewalks, and sidewalks repaired because of conflicts with trees. This blog is intended to help informed community decision making, now and into the future. Solutions will remain situational.
Landscape Design for Resilience
The best way to mitigate conflict with tree roots and pavement is to design a landscape with plenty of space for roots to establish. Species selection and planting site modification make a difference with landscape longevity. The reality is that these landscape and hardscape conflicts arise years later, thus requiring maintenance and/or removal of trees, sidewalks, and asphalt. This is intended to be informative. Neighborhood and tree specific management strategies should be discussed with an International Society for Arboriculture (ISA) Certified Arborist: https://www.treesaregood.org/.
Let’s be real; a lot of tree conflicts begin in the landscape design or installation phase. When we put a tree in an antagonistic location, it will require constant maintenance while still being problematic. Trust me, I get A LOT of calls about landscape issues for the wrong plants in the wrong place in brand new developments. More interestingly, I get calls about old developments with super mature trees that cause sidewalk and asphalt buckling, a costly challenge and safety hazard. These types of issues can even make tree lovers question their street trees. I have been hearing about insurance issues with trees lately, too. Think right plant, right place now and decades later, plus a few hurricane batterings. That is how to pick a good tree!
It is recommended Landscape Architects design for the horticultural needs of the trees first, environmental benefits next, then ensure the codes and ordinances are followed last. Of course, aesthetics must be considered alongside local codes, a real strength of many Landscape Architects. Perhaps tree roots can become a feature in landscape design, similar to the role of sculpture and architecture?
First, it is good to understand options for working with the trees. Mature trees add monetary value to homes while also providing environmental benefits such as cooling temperatures and wildlife habitat. Here is a good publication from the industry, Bartlett Tree Experts: https://www.bartlett.com/resources/sidewalk-repair-near-trees.pdf.
UF Emeritus Professor Ed Gilman explains a classic landscape design dilemma that can be avoided with good planning for happy trees. Trees are installed in parks with the vision of a fully enclosed canopy. If the trees are happy, healthy, and growing into a fully enclosed canopy as envisioned, they will grow and the walkways will likely be damaged. Alternatively, the trees grow poorly and the walkway remains intact. Since trees take time to grow and return benefits, planning for the long term health and maintenance of both the trees and the sidewalks is key. Plan and budget for the trees long beyond installation!
Next, where conflicts between landscapes and hardscapes are not realistic to mitigate, tree replacement planning is key. There are many trees species to consider. Here are UF resources to help discover suitable trees:
UF/IFAS Florida Trees for urban and suburban sites Tree
Selector: https://lyra.ifas.ufl.edu/TreeSelector.html
UF/IFAS Urban/suburban design to support trees: https://hort.ifas.ufl.edu/woody/urban-design.shtml
UF/IFAS EDIS How much space does my shade tree need? Planting space recommendations for medium and large trees in Florida cities: https://edis.ifas.ufl.edu/publication/EP592
UF/IFAS Blog Conflict between trees and streets? Yes, but UF scientists find equation to ease tension: https://blogs.ifas.ufl.edu/news/2020/03/09/conflict-between-trees-and-streets-yes-but-uf-scientists-find-equation-to-ease-tension/
UF/IFAS Bookstore Trees of North and Central Florida: http://ifasbooks.ifas.ufl.edu/p-1258-trees-north-central-florida.aspx
Purchase Trees
Finally, you may be interested in finding specific species of trees at nurseries and wholesalers.
Plant Search: https://www.plantsearch.com/
PlantAnt: https://www.plantant.com/
Digging deeper and some disclaimers!
Numbers can be helpful when decision making. The comparisons of tree CO2 sequestration and concrete CO2 emissions are broad generalizations based on real numbers. The real numbers are not necessarily for Florida species or Florida situations. Here are resources used to help with understanding carbon emissions and sequestration related to trees and sidewalks and resources used to make generalizations about tree and sidewalk CO2 sequestration and emission.
Comparative Ecosystem Benefits of Common Urban Trees and Palms in South Florida https://edis.ifas.ufl.edu/publication/EP604
Cement and Concrete: The environmental impact https://psci.princeton.edu/tips/2020/11/3/cement-and-concrete-the-environmental-impact
USDA The Power of One Tree – The Very Air We Breathe https://www.usda.gov/media/blog/2015/03/17/power-one-tree-very-air-we-breathe
Thank you! Feedback?
Thank you to Dr. John Roberts, a real UF/IFAS Tree Expert and UF/IFAS Commercial Horticulture Extension Agent for Palm Beach County, for help checking facts and being generous with wisdom. I would also like to thank Dr. Heather Kalaman, UF/IFAS Extension Orange County Florida Friendly Landscaping Agent, for sharing helpful resources and experiences from her time working at Bartlett Tree Experts. The International Society of Arboriculture is an incredible resource for education and certification. The Florida Urban Forestry Council is an excellent resource for managing and improving Florida’s incredible tree canopy.
If there is more up to date or accurate information, please email me hwooten@ufl.edu! This is the type of research that communities need to make informed decisions, and my numbers are very general. Thanks for loving trees!
