Tim Johnson

Street trees are on the front line of urban forest service delivery, supporting neighbourhood character, human health, waterway health, biodiversity, tourism and business vitality. In order to deliver these benefits, street tree populations must be both diverse and well suited to the local conditions. Currently, urban ecosystems are experiencing unprecedented levels of warming and shifts in rainfall patterns due to climate change, which means tree species selections that have succeeded in the past may fail to do so in the future. Therefore, it is vital that a range of climate ready tree species are identified to ensure the resilience of urban environments to climate change. This can be achieved through street tree trials.

As part of TREENETs long term promotion of street tree species trial research, we are proud to promote the use of the newly released “How to” guide for street tree species trials, developed in collaboration with the national Which Plant Where project. Version 1 of the Guide provides an easy-to-follow, step-by-step plan to designing, implementing and monitoring scientifically rigorous trials of street tree species in an urban context. TREENET is also supporting partnerships between local government and nurseries in growing lesser known species for trials and sharing of trial results.

Presented by Dr Lyndal Plant and Dr Tim Johnson

Dr Tim Johnson

Dr Tim Johnson is an arborist, green engineer, conservationist and researcher who works to better connect urban communities with nature in their gardens, streets and parks. Tim’s interests focus on green engineering design to support trees and urban vegetation so interactions between plants, infrastructure, water and soil can deliver maximum community and environmental benefit. His experience ‘on the tools’, in technical, strategic and research roles in the private and public sectors underpins his practical approach to applied interdisciplinary research.

Through his role as Sustainable Infrastructure Engineer working for the City of Mitcham in South Australia, Tim leads research based on experiments designed into working infrastructure in the public realm. These studies serve as demonstrations of nature-based solutions to challenges associated with urbanisation and climate change. The effectiveness of this approach saw Tim named amongst the top 20 most influential people in local government in South Australia by the state’s media in 2020.

Current research projects include investigating the effects of stormwater harvesting on transpiration rates in urban trees, the capacity of urban soil to retain stormwater, and the effects of stormwater infiltration on reactive soil. Tim is currently supervising two PhD students who are researching the stormwater management benefits of dispersed, small-scale infiltration devices and the climate moderation impacts of stormwater infiltration into tree root zones.

Tim serves on the Advisory Board and Management Committee of TREENET Incorporated and is a member of several industry groups including the Institute of Public Works Engineering Australasia, Arboriculture Australia, the International Society of Arboriculture and the South Australian Local Government Urban Forest Alliance. He is an Industry Adjunct at the University of South Australia-STEM and an Adjunct Lecturer at Flinders University. He has served on the Significant Tree Committee of the National Trust of South Australia (2002 – 2012) and the South Australian Urban Forest Biodiversity Program (1997–2006).