Scattered trees ‘of huge benefit to all’

Trees standing alone and in small groups in Britain provide billions of pounds worth of benefits to people every year, according to a new report. The trees capture climate-heating CO2, reduce toxic air pollution and slow the flow of rainwater, cutting flood risks.

The value of woodlands has already been estimated but the report is the first to calculate a value for trees in British gardens, parks, fields and streets. There are millions of such trees, covering a combined 750,000 hectares and making up 20% of all the nation’s trees.

It found the value of the services from non-woodland trees ranged from £1.4bn to £3.8bn a year, depending on the methodology used. The researchers said the estimates were conservative, as many benefits are hard to quantify, such as the boost to wildlife and mental health.

A large individual tree, with a canopy diameter of 30 metres, provides hundreds of pounds of benefits a year, the report found. It also estimated separately the average replacement cost of a tree at £2,500, though the largest trees can be valued at over £100,000. In total, the report valued non-woodland trees at £429bn. The researchers said their work could be used by local authorities to justify the costs of protecting and planting trees at a time when budgets are tight.

Kieron Doick, head of the Urban Forest Research Group at Forest Research and the lead author of the report, said the importance of single and small groups of trees struck him on a recent walk. “As I walked home, I was passing trees all around my town, along the highway, single ones in people’s gardens, some at the intersections,” he said. “It represented to me the diversity and coverage of the trees that are in our everyday lives, but are not in woodlands.”

He added: “The numbers are substantial. These trees are at least as valuable in terms of providing benefits to people as woodland trees and we still aren’t even considering all of the benefits.

“This research will help support decision makers to justify the spending on the resource management, research and maintenance of our non-woodland trees in the same way they do our woodland trees.”

The report found the largest economic benefit from the nonwoodland trees is the removal and storage of CO2, which accounted for a half to two-thirds of the benefit, depending on the methodology used. The removal of air pollution was also significant, contributing a fifth to a third of the benefits.

Smaller but important benefits included cooling local temperatures on hot days and screening people from noise pollution. Single urban and rural trees and groups of trees less than 0.5 hectares in area were included in the analysis.

Earlier research estimated the canopy cover of trees in 283 towns and cities in England at an average of 16%, with another study recommending this should rise to a minimum of 20%. A citizen science project to map urban canopy cover in Britain is being run by Forest Research and partners. Doick said the state of urban trees varied considerably: “In some cities, their population will have a very high percentage classed as in very good or excellent health. In other places, it will be less so.”

The government announced this week that 57 local authorities across England had received nearly £10m through the Woodland Creation Accelerator Fund to kickstart treeplanting activity.

Trudy Harrison, the forestry minister, said: “Our trees, forests and woodlands are the nation’s lungs and serve as a powerful weapon in the fight against climate change. At a local level, trees are the lifeblood of communities, essential to supporting wellbeing.”

Adam Cormack of the Woodland Trust said: “This important new research shows the extraordinary financial value of the trees in our streets, our parks and our countryside, [which] should be worthy of the highest level of protection. Yet, we know this isn’t the case. For example, eastern England has lost 50% of its large trees in the past 150 years.”

The “incalculable cultural value” of trees was not covered by the research, Cormack said. “This is especially true for our oldest and most important trees, which don’t have the automatic legal protection that most of our wildlife and old buildings have. These astonishing trees are our inheritance from history, and we should be treating them like national treasures.”

Mike Childs, head of policy at Friends of the Earth, said: “Estimating the economic value of trees is fraught with difficulties and inevitably fails to capture all the benefits. But the government shouldn’t need this type of exercise to realise that we need more trees in our towns, cities and countryside.

“The government’s suggestion of increasing tree cover in England from 14.5% to 17.5% by 2050 is completely inadequate. It should be aiming to double tree cover and ensure that every street and neighbourhood reaps the undoubted benefits.”