Building Urban Tree Resiliency by Mitigating Below Ground Infrastructure Techniques

2020 Andy Kaufman, PhD, University of Hawaii

This project was conceived through group of public and private urban forest advocates in Hawaii with the main objectives to: 1) Develop root zone strategies for the planting and maintenance of urban street trees, 2) Develop better root zone strategies to assist in reducing infrastructure damage and maintenance, 3) Apply these strategies to increase the resiliency of newly planted urban trees against natural disasters, 4) Complete the first long term comprehensive tree study for tropical/subtropical environments; to obtain vital planting, growing, and maintenance information for all urban trees. This was done with the selection, installation and establishment of 50 trees (Rainbow Shower (Cassia x nealiae) and Kou (Cordia subcordata) species; along with simulated sidewalks; and the testing of three planting pit sizes (3’x3’, 4’x4’, & 5’x5’), Root barriers, Root paths, and Silva cell below ground root mitigation treatments (Root barriers, Root paths, and Silva cells are below ground installation treatments to help roots grow under roads and sidewalks without causing damage). A main benefit of conducting this study in Hawaii is instead of one short growing season to collect research data per year, as is done in temperate climates, Hawaii’s warm climate allows for constant growth resulting in 2-3 times of data collection. For this project, almost 15 years of above and below ground tree data have been collected in half the time. The expected outcomes of this project are to clarify the proper below ground planting methods that are more effective for urban tree plantings. Anticipated benefits from this research include:

1. Improved tree health

2. Reduced tree infrastructure conflicts

3. Reduced safety issues

4. Urban tree root zone  strategy scope

5. Develop urban tree installations and maintenance guidelines

Year: 2020

Funding Duration: 2 years

Grant Program: Hyland R. Johns Grant

Grant Title: Building Urban Tree Resiliency by Mitigating Below Ground Infrastructure Techniques

Researcher: Dr. Andy Kaufman

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For more information on this project, contact the researcher via TREE Fund at