Trees in the Urban Environment [CIRIA Conference – 15 July 2014]

The report of this conference can also be found on The Tree Council’s website. Below is the article.

The Tree Council CIRIA


Conference report by Dr Ryan Stevenson of Teratrees, which is a member organisation of The Tree Council.

This informative conference was chaired by Joanne Kwan of CIRIA on a pleasant summer’s day at The National Archives, Kew.

Ross Cameron from the University of Sheffield kicked off with Trees and Urban Green Infrastructure – Future Functional Cities. The vast benefits of trees presented to us in total as he did, continue to produce wonder and help us to reaffirm our actions. It was clear that trees are integral to human communities and are under-appreciated in all that they provide.

Continuing with that theme, Jim Smith from the Forestry Commission argued convincingly that we should perceive trees as an asset which would create parity with other urban infrastructure. This would mean the logic of standard asset maintenance management which is typically 0.5 to 1.5 % of the asset value and would also imply the management of London’s urban forest as a single resource. Initiatives by the i-Tree project are looking at this presently.

Emma Clark from the HTA updated us on phythophthora, chalara and Candidatus Phytoplasma ulmi in the UK, and with respect to horticultural trade. It is rather worrying regarding ash trees – Defra’s plans include toolkits, increased communication and plant passporting. Draft EU regulations are under discussion.

After lunch, Keith Maynard from The National Archives informed us regarding the water and tree management on their 4.9 hectare grounds, including the provision of wells. Initially it was thought pond level reduction was caused by nearby trees, but they discovered it was natural evaporation.

Martin Gammie (CwT Ltd) discussed trees in urban landscapes, also referring to a document to be published by the Trees and Design Action Group called Trees in Hard Landscapes. This outlines the approach when introducing urban trees, especially considering their current 25 % failure rate and average lifespan of 12 years. Importantly, more awareness is needed in selecting species and increasing collaboration between planners and planters.

Dean Bowie of Green Blue Urban was the final presentation where he showed their research and technology with introducing urban trees e.g. specific cavities and structural supports which when combined with good soil lead to much healthier trees. Root aeration is very important in urban landscapes as well as managing water, and their products tackle these challenges.

During open discussion and post-conference feedback, it is apparent that attendees see the need for more influence at the planning level with respect to trees to counter developer interests in maximising building volume. This means increased collaboration between all parties, while local authorities and TfL need to introduce tree strategies for developers, including their maintenance. Involving mortgage lenders and insurers would also be beneficial.

In closing, it was apparent from the presentations as well as London’s campaign to increase canopy cover, that trees will be of increasing importance and our approach now will greatly affect their future, and ours.