Local residents turned out tonight to learn more about the upcoming Alton Road elevation project and its impact on the tree canopy. The project, which also includes the installation of stormwater pumps to help mitigate the impact of sea level rise, will be done by the Florida Department of Transportation (FDOT). When FDOT informed the City of Miami Beach that the existing tree canopy could not be saved, Commissioners asked for an extensive community outreach effort and they got it.
Tonya Daniels, City Communications Director, said staff mailed notices about the project to 352 homes on Alton Road then they knocked on all of those doors speaking with residents or leaving information if they weren’t home. Next they were invited to tonight’s meeting and offered a survey to give feedback. One more mailing about the project will include a link to the online survey for residents who could not attend.
Large poster boards with project details were set up around the room while City staff answered questions. Four boards provided detailed explanations and illustrations on the impact to the existing landscaping. The proposed plan “would remove the existing canopy and replace it with a mix of smaller native trees and palms."
The issue is the impact of the road elevation and underground utility work on the root systems of the trees. Raising the soil level around an established tree drastically reduces the oxygen supply to the roots and, as a result, many will not survive. According to the City’s materials, “90% of the fine roots that absorb water and minerals are in the upper 6 to 12 inches of soil … It only takes a few inches of added soil to kill a sensitive mature tree.” Digging and trenching during the project will also impact the roots, which can extend a distance one to three times the height of a tree. Severing of the roots is likely. Root loss, not only threatens the health of a tree, it also increases the potential for a tree to fall. A number of the trees are already in failing health.
Overhead power lines also create an issue. The City says many trees “are in conflict with the power lines and may have to be removed.” FPL regulations state that around utility lines, trees need to be less than 20 feet tall. Medium trees must be set back a minimum of 20 feet; large trees must be set back a minimum of 30 feet; and large palms must be set back maximum palm frond length plus three feet. “If no overhead lines exist or lines are relocated, large canopy trees to replace the existing trees will be planted” according to the information presented.
More discussion to come at the Commission level.
The construction, which involves Alton Road from Michigan Avenue to 63rd Street, is anticipated to begin in the fall of 2020.
More details on the project and landscape illustrations