Using robotics to detect footpath displacement caused by tree roots: A proof of concept

Abstract It is well-accepted that urban trees provide many benefits to society, but there are costs associated with their establishment and maintenance. Some indirect costs of juxtaposing trees with urban infrastructure are linked to the way in which tree roots interact with hard surfaces such as footpaths (sidewalks), which can result in expensive repairs and in some instances, tree removal. There is a need to understand the complex interactions between tree roots and infrastructure, to inform strategic planting and balance the needs of all stakeholders. In this short communication, we introduce a simple, cost-effective method for quantifying footpath displacement using Arduino robotics and provide the schematics and coding as an open-source tool. Using an ultrasonic sensor, the robot generates a 2.1 m long, two-dimensional profile of a given surface. The accuracy of the robot is validated with objects of known size and was subsequently field tested using 15 Liquidambar styraciflua growing in a suburban street. The robot allowed us to quantify the maximum (highest vertical point) and total (the area under the curve) displacements in the footpath surface. Trunk diameter and proximity to the footpath were significant predictors of displacement at P