The importance of trees as part of Sustainable Drainage Systems is becoming more widely understood and their delivery under the 4 pillars of SuDS – Quantity, Quality, Amenity and Biodiversity.
Many SuDS schemes now include tree pits produced by companies like BlueGreen Urban producing off the shelf systems.
Aside from Tree pits, trees can also be integrated as part of many SuDS components such as basins and swales to improve the effectiveness and benefits offered by the SuDS component. As well as the tree canopy producing losses (reduction of runoff into the sewer), trees also loosen up the soil profile meaning that there is more potential for runoff to seep into the ground, which will occur even on clay soils.
Careful consideration is needed for specification of the tree species and location to ensure that maintenance does not become an onerous responsibility. McCloy Consulting are in the process of designing an urban renew scheme for a full housing estate in London which will be underpinned by the introduction of trees as a way of managing runoff and facilitation of disconnection from the sewer.
The importance of trees, and the reintroduction of new trees to our planet was highlighted by a recent article published by the Guardian which articulated that Tree planting as an approach to handling climate change may be unmatched in terms of effectiveness.
The article discussed a study based on data collated by Crowther’s Lab. It identified 1.7bn hectares of treeless land that could support 1.2tn trees, highlights that the matured trees could absorb almost two thirds of the carbon that has been released into the atmosphere by human activities.
Professor Tom Crowther, who led the research, stated that the study proved ‘restoration isn’t just one of our climate change solutions, it is overwhelmingly the top one’ and descried the approach as ‘overwhelmingly more powerful than all the other climate change solutions proposed.’
The research is based on 80,000 high resolution satellite images. Tree cover in these images was measured by hundreds of people, and artificial intelligence combined the data they provided alongside key soil, topography and climate factors in order to show where trees could grow.
René Castro, assistant-director general at the UN Food and Agriculture, called the study the first ‘definitive evidence of the potential land for re-growing forests, where they could exist and how much carbon they could store.’
More than ever before, efforts to do something about climate change are beginning to gain momentum and support. Crucial concerns with ensuring the success of any reforestation scheme are avoiding monoculture plantation forests and respecting local and indigenous people.
Therefore, in their own small way from a wider planet context, the integration of trees into SuDS schemes will further assist in combating the impacts of Climate Change and is something that should be considered whenever devising the SuDS strategy for a site and meeting the requirements of Climate change policies embedded within the Local Area Plan.