Report proves economic and environmental value of lone trees

Trees outside of woodlands remove billions of tonnes of combustion pollutants and should be protected, as government says it is committed to trebling tree planting rates by 2024

The economic value of the UK’s individual trees has been calculated in a new report from Forest Research, the research agency of the Forestry Commission, and Defra. They have estimated the total value at £3.8 billion.

The sum takes into account the role of trees outside woodlands in tackling air quality, climate change, slowing the flow of rainwater and damping down noise. The report says that this type of tree covers a combined 750,000 hectares and makes up 20% of all the nation’s trees.

Kieron Doick, Head of the Urban Forest Research Group within Forest Research said: “These trees are all around us: in our gardens, along our roads, in parks and green spaces. Understanding their value can help make sure councils and landowners invest in the planting of more trees.”

Adam Cormack, at the Woodland Trust, added that the research shows the “extraordinary financial value” of these trees, which should be worthy of the highest level of protection. “Yet, we know this isn’t the case,” he said. “For example, eastern England has lost 50% of its large trees in the past 150 years.”

“A single tree reduces the PM2.5 concentrations behind it by 15%. So, it's fascinating to see what that looks like at scale, removing billions of tonnes [of combustion pollutants].”

Tim Smedley, author of Clearing the Air: the Beginning and the End of Air Pollution, said that the report added “helpful numbers to what we all intuitively know”. 

He said: “A previous report found that a single tree reduces the PM2.5 concentrations behind it by 15%. So, it's fascinating to see what that looks like at scale, removing billions of tonnes – and billions of pounds sterling – of not just PM2.5, but other combustion pollutants including NOx and SO2."

Daniel Baker, acoustics expert and Director of Broodbakker Acoustic Consultants said that the presence of trees and foliage has both direct and indirect acoustic benefits for environmental health.

“Direct effects can include the scattering of sound waves by tree trunks and branches, conversion of sound energy to heat moving through foliage and increasing the porosity of ground. For example, ground becomes porous and absorptive where tree roots grow or where ground is covered in foliage.

“There are also indirect benefits. Trees and foliage attract birds. Birdsong provides sound with a natural and positive connotation. Psithurism (sound of rustling leaves) is also a natural sound likely perceived as beneficial and may, in certain circumstances, provide temporary masking of other man-made sounds.

“Even small tree belts and/or foliage between residential gardens and industrial/commercial premises may provide indirect benefits such as visual screening even where the measurable acoustic benefit (attenuation) using a sound-level meter may be negligible. A 1dB noise reduction would not be perceptible to anyone but it forms part of a wider positive state of affairs and benefit to the community.”

Trudy Harrison, Forestry Minister said: “As set out in our England Trees Action Plan, we have committed to trebling tree planting rates in England by 2024 and by quantifying the significant value of trees, this research will help to incentivise planting in our communities across our country.”

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