Bristol’s One City Plan, published in January, is calling for the city’s tree canopy cover to be doubled by 2046 to combat climate change and air pollution, protect biodiversity and promote health and well-being. Meanwhile, a new iTree Eco survey puts Bristol’s canopy cover at around 12%, some way below England’s urban average of 16%.
Bristol City Council, the Woodland Trust, the Bristol Tree Forum and Forest of Avon Trust are working to produce an action plan to set out how this ambitious goal can be delivered and funded. The latter has already set up an online survey to engage members of the public, and points out that the target could be achieved if everyone in Bristol planted just three trees.
Meanwhile, the council has taken steps in its draft local plan, currently being finalised, to give 159 open spaces in the city the protection of "local green space" status under the National Planning Policy Framework, with a further 410 being protected as "reserved open spaces".
But these are under pressure. The local plan also calls for "over 33,500 homes" by 2036. Mayor Marvin Rees explains: "As we develop more homes, businesses and communities, it is essential that we carefully conserve open space infrastructure such as parks, playing fields, nature reserves and the city’s lungs of natural space."
The council’s parks development manager Richard Ennion describes the canopy doubling target as "probably the most ambitious in the UK", but points out: "We aren’t starting from scratch. We already have the 'One Tree Per Child' programme, which plants around 6,000 trees a year, mostly in and around schools. We get a commitment that they will be looked after and some are already turning into nice woodlands or orchards. Over 30 years, that can make a 28% contribution to the tree cover target."
The target "is doable, but not by business-as-usual", he says. "There aren’t vast sums on the table and these need to be found. But we are actively engaged with many organisations, which we may ask for cash, for help or to accommodate planting on their land."
Ennion explains: "There is a correlation between tree cover and people’s health and well-being, so it’s a cheap way to address that. The Government is starting to recognise this and the other ecosystem services that trees provide, which is an opportunity to ‘marketise’ trees with the organisations responsible, and the iTree survey gives us the facts and figures to back this up. Though clearly it’s a challenge to convert that into investment."
Another avenue is to harness philanthropic individuals and organisations, along lines established in the USA. Last year, a public-private partnership, City Funds, was set up as a conduit for this. "We provide the links for potential funders — we have the land and, if they want to see it improved, we can work together," says Ennion. "The tide is turning on this, and the One City Plan can be a stimulus for it."
Individuals and organisations can also sponsor a tree directly online via the "TreeBristol" programme. The price of £295 covers the tree, its planting and two years’ aftercare. The scheme has supported "reasonable numbers" of new trees, he says, while more widely, trees will be a component of the Nature Recovery Network proposed by the West of England Nature Partnership of local authorities and non-government organisations. "There are a lot of ways to get to the same point," says Ennion.
Then there is the question of maintaining the city’s current maturing tree stock. The Bristol Tree Forum, which in theory works in partnership with the council, has in practice been critical of the local authority’s ongoing care and replacement of existing trees, which it says works against the canopy cover target.
Forum chair Mark Ashdown tells Horticulture Week: "It is very difficult to replace existing canopy when it has gone. All too often, majestic planes and limes are replaced by trees of limited life expectancy that will never become large or replace the cover that has been lost. What is needed is a management plan that looks at the best balance between maintaining existing trees and planting new ones while increasing tree canopy at the same time."
Ennion responds: "We have an eight-for-one policy of replacing mature trees lost to development, or £765 per tree that will maintain it over its lifetime. It has to be financially sustainable. A large tree on a three- or four-year pollarding cycle is expensive and hazardous, and has lower canopy value. The difference between that and a tree that will max out at the right size with much less maintenance is limited."