Saturday, 21 October 2017

The Importance of Urban Street Trees

The Victorians knew a thing or two about building towns and cities we appear to have forgotten. Municipal public parks, cemeteries and other public green spaces are one of the greatest legacies of Victorian Britain. They also planted a very large number of street trees and crucially, they kept the trees that were already there, by building streets and houses around them.

It has been estimated that by 2030, 6 out of 10 people will live in cities. By 2050, this will increase to 7 out of 10. People are more isolated from nature than ever before, and access to nature within the urban environment is more important now than ever.

The Woodland Trust believes that we are taking our urban green spaces and our urban street trees for granted and do not value them sufficiently:

Town and city planners have recognised the importance of street trees and green space for years, but unfortunately the drastic cuts in the budgets of local authorities in recent years has meant that these important parts of the urban environment are being neglected, or that their protection is being removed, and the land developed. A tree can take hundreds of years to grow to maturity, but the benefits it provides is staggering and far outweighs any maintenance costs. Once a tree has gone, it has gone forever.

The Forestry Commission has outlined the main benefits of mature street trees here:  

The tree canopy can:

  • Reduce the urban heat island effect by shading and evapotranspiration
  • Reduce pollution by intercepting particulates and absorbing greenhouse gases
  • Reduce flooding by intercepting rainfall.
Clearly, mature street trees need to be a part of any strategy to counteract climate change, or inner city air pollution, but the environmental importance of mature trees cannot be underestimated. They also support a wide range of animals and other plants, supplying food, shelter, shade, and nest sites. Street trees support the birds that come to your garden and the insects that pollinate your garden flowers.

Living in an urban area with green spaces and street trees also has a long-lasting positive impact on people's mental well-being and physical health, by offering an environment for exercise and reducing levels of stress. Something the Green Gym is very well aware of.

However, you may be surprised to learn that trees in urban areas are also known to provide a wide range of other social and economic benefits. The incorporation of trees into urban development plans improves the aesthetics and environmental quality of urban areas which can lead to increased inward investment and the provision of jobs.  Research has shown that nearby trees can increase the property value of your home by 15% or more. So, removing street trees will actually reduce the value of your property. Other research has shown that crime is reduced in neighbourhoods with street trees, and that traffic travels more slowly on the roads, and reduces incidents and the severity of accidents.

Sycamore, London Plane, Poplar, Horse-chestnut & Lime trees are the most common trees found on LB Bromley’s streets.  According to Cornell University: it is important to carefully choose tree species that will survive the pollution, heat and salt in the urban street environment. The best policy is diversity, as monocultures of one particular tree species can lead to diseases and increases in damaging insect populations. The trees most likely to survive are those that have already proved themselves; those mature trees that are already there.

The Vernon Oak is a street tree in Sheffield that is 150 years old. It was there before the street or the houses and was a boundary oak at the edge of a field. Sheffield City Council plans to cut this healthy tree down and replace it with a more manageable sapling. It has plans, already underway since 2012, to cut down thousands of similar trees. If the saplings die they promise to replace them with another. It would be several lifetimes before these saplings have the same ecosystems established around them, and in the meantime the benefits provided, including shade and canopy cover, but also those social and economic benefits, are lost. It has been calculated that 60Ha of Sheffield canopy cover has already been removed, and Sheffield City Council show no signs of stopping yet. Last month, in London, LB Wandsworth cut down Chestnut Avenue on Tooting Common and are replacing every mature tree which was there with immature Limes.

The case made for removal is often that the trees are dead, or diseased, and are health and safety risks. No one is asking that dead trees are not felled, but all trees do carry some disease and this can often be safely managed. Damage from tree roots to roads, pavements and walls can be managed too, with engineering solutions that exist that allow trees to remain. These solutions can be more expensive but the priority should be to do everything possible to keep the mature tree. Where trees must be felled then saplings should be planted among the remaining trees to provide a range of tree ages and a diversity of types. The cutting down of every single tree on a street is simply environmental vandalism.

If cost was the only problem, Trees for Cities have, in the case of the Vernon Oak, made an offer to pay for the repairs to the pavement:

The offer has not been taken up yet, although the council says it is in “discussions.” Meanwhile, the council continues to take legal steps against protesters, and several are due in court on 27th October. It has all become very heated, without very much light, and Councillors Tweet (a Tweet since deleted) that they are “contemptuous of idiots” who disagree with the council policy, or they claim that protesters have spread “misinformation.” However, I haven’t understood what information is misleading concerning the council policy, as it appears quite clear, even from the mouths of the councillors themselves.

Sheffield Council also use the same excuse as do LB Bromley, asking which other service you would cut instead to fund non-statutory duties. Services cost the price that they cost. If you pay less then you get substandard services. It is their fundamental job to balance budgets while maintaining services at the same standards or better.

For me, the bottom line is that mature urban street trees are more important than pavement and road repairs, and possibly even more than house foundations. Children’s playgrounds can be moved, mature trees are more difficult. We would not demolish a grade one listed building because it was too close to a widened road. 

Why do we not value our trees in the same way?

David Fergusson BSc (Hons) (Sheff) MSc. DIC 

Tuesday, 3 October 2017

Natural Health Service

New research by The Wildlife Trust supports the idea that nature could be widely prescribed by doctors as a therapy, easing the burden on the NHS.

The physical and mental health benefits of gardening and working outdoors volunteering is something that Green Gyms have known about for many years. Penge Green Gym is now over six years old, but the Green Gym concept was the idea of Dr William Bird, and the first Green Gym was piloted in 1997 in Sonning Common.

Green Gym is a registered trade mark of The Conservation Volunteers (TCV.) Here is a list of other TCV Community Groups including Green Gyms. If there isn’t a Green Gym in your location, why not start your own?