Saving Our Street Trees - An innovative root barrier program that looks to reduce infrastructure damage and save our mature urban forest
In 2017, TOC was approached by University of Hawai‘i professor Dr. Andrew Kaufman to participate in a research program that has been designed to find alternative root barrier methods that would work in Hawai‘i to greatly reduce the number of mature street trees that are removed annually due to infrastructure damaged caused by their roots.
The initial project had already been underway for a few years but it was at this point that increased data collection and research needed to be conducted in order to understand the full impacts of the three different root barrier methods under consideration (standard root barriers, root paths and Silva cells). Due to the immense potential that this research could have on preventing mature trees from being constantly removed and replaced with new smaller trees, and the research experience that TOC’s Programs Director, Myles Ritchie, has in the field, this seemed to be a natural fit.
Now, a year and a half later, the data that has been acquired has recently been published in the May/June 2018 issue of the Landscape Industry Council of Hawai‘i’s (LICH) Hawaiiscape Magazineshowing the progress that has been made and the potential findings that will be seen when the final data is analyzed in two years’ time. Below is an excerpt from the article that highlights the goal and benefits of the research: "This research will be one of the first projects addressing tree installation, root zone strategies, and mitigating existing tree/infrastructure conflicts in tropical municipal landscapes. It will begin to generate techniques for proper tree selection, installation, and maintenance which could be employed statewide. These kinds of techniques will not only improve the aesthetic quality of Hawaii’s public landscapes for visitors, and residents, but has the potential to save the State thousands of dollars per year in urban forest amenity replacements and maintenance practices. In addition, this project will help in the safety of urban trees in relation to sidewalks and streets from improper tree selection, installation, and maintenance practices due to the current lack of knowledge of how trees function in urban tropical environments, as opposed to those in more temperate environments. The results of this research could be immediately applied to future HDOT as well as C & C Honolulu urban tree planting projects. This could begin to drastically change the way trees are selected, installed and maintained in the State of Hawaii, thus improving the aesthetic, social, and safety of urban landscaped streets while becoming a viable economic practice” (Kaufman & Ritchie, 2018).”
Moving forward, the results of the research should help provide new information to those who conduct street tree plantings and infrastructure maintenance. From this, we should see a healthier and more mature urban forest throughout the state that also sees a decrease in the amount of infrastructure damage caused by tree roots, while at the same time, keeping sidewalks safe for all to use by mitigating the constant battle seen between trees and urban infrastructure.
Source: Kaufman, A., Ritchie, M. “Mitigating Infrastructure Damage by Trees: Hawaii’s First Research Study on Urban Tree Installation Strategies”, Hawaiiscape, Published May/June 2018.
Greenleaf is the online newsletter and blog of The Outdoor Circle. Here you will find updates on the projects and accomplishments of our many branches throughout the state, as well as programs with statewide impact.