A recent study of the publicly-owned trees in the London Borough of Southwark has shown the value of the asset managed by the local authority. The study, using i-Tree Eco and carried out by urban forest specialists Treeconomics, discovered that the trees owned and managed by the London borough would have a replacement cost of more than £165m.
In addition, using Southwark’s own tree inventory, Treeconomics calculated that the trees managed by the council remove in excess of 21t of air-borne pollutants, valued at more than £135,000 each year, and store over 57,000t of carbon, valued at over £14m per year. They also divert over 35,000m3 of storm water away from the local sewers each year, which is worth an estimated £21,183 in avoided stormwater treatment costs. The benefits provided by these trees will grow as the trees do.
The benefits linked to health and wellbeing cannot currently be measured using i-Tree; but Treeconomics says 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.
As a follow up to the i-Tree Eco inventory project, Southwark 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% to 34.9%
Cllr Rebecca Lury, Cabinet Member for culture, leisure, equalities and communities, comments: “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 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 provides to local people and better inform our current and future management, of Southwark’s urban forest.”