TREE officers are often recognised as ‘custodians of the urban forest’, managing the public tree estate for the common good.

A recent study of the publicly owned trees in the London Borough of Southwark has, yet again, demonstrated the huge value of the asset they manage. The study, using i-Tree Eco, and carried out by urban forest specialist Treeconomics, discovered that the trees owned and managed by the London borough would have a replacement cost of over £165 million.

In addition, using Southwark’s own tree inventory, Treeconomics was able to calculate that the trees managed by the council remove over 21 tonnes of air-borne pollutants, valued at £135,000 plus each year, and store over 57,000 tonnes of carbon, valued at over £14 million per year. They also divert over 35,000 cubic metres of storm water away from the local sewers each year, which is worth an estimated £21,183 in avoided storm water treatment costs. Furthermore, the benefits provided by these trees will grow as the trees do.

This study highlighted the many ecosystem services that trees provide. However, the benefits linked to health and well-being cannot currently be measured using i-Tree; so the annual benefits figure of almost £400,000 is certainly an underestimation.

By valuing the benefits that its trees are providing, Southwark Council now has an evidence base with which to mitigate for development impacts, inform land use changes and, through planned intervention, avoid losses to its natural capital. The results of the study will certainly help the council to make informed management decisions about its green infrastructure.

The urban forest is dynamic and needs to be annually replenished through strategic new tree planting. As a follow-up to the i-Tree Eco inventory project, Southwark then commissioned Treeconomics to create a Tree Planting Opportunity Map, to highlight areas with tree-planting potential throughout the borough. The mapping exercise showed that if, over time, all actual plantable space was to become tree covered, Southwark’s canopy cover could increase from 19.9 per cent to 34.9 per cent.

Councillor Rebecca Lury, cabinet member for culture, leisure, equalities and communities, commented: “In Southwark, we are committed to nurturing our existing 82,000 trees, and planting more. As an inner London borough, we value the vital role that our trees play in helping to improve air quality, as well as the other multiple benefits they offer to local communities and neighbourhoods. We welcome Treeconomics and their expertise. This commission will help us to further quantify the environmental benefits that Southwark’s trees provide to local people and better inform our current and future management of Southwark’s urban forest.”

Forestry Journal remains dedicated to bringing you all the latest news and views from across our industry, plus up-to-date information on the impacts of COVID-19.

Please support us by subscribing to our print edition, delivered direct to your door, from as little at £69 for 1 year – or consider a digital subscription from just £1 for 3 months.

To arrange, follow this link:

Thanks – and stay safe.