The UK’s urban forest

What is an urban forest, why is it important, and what are the threats?

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A view of the London skyline in the background with people sat on grass in Primrose Hill park in the foreground

Forests provide irreplaceable benefits for the health of people and the planet, but how do urban areas contribute to this and the UK’s tree canopy?

What is an urban forest? 

An urban forest includes all trees and shrubs within the parks, gardens, streets, woodland and open spaces of a town or city as well as the wildlife living amongst them. This also includes any trees that are planted on land belonging to private landowners, institutions, and local authorities.   

Wherever you are in the UK, you can look at your local area’s canopy cover on the Canopy Cover WebMap. 

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Houseboats on a canal surrounded by willow trees

What is the difference between forests and woodlands? 

Historically, forests referred to tree covered land (sometimes including open grassland, heath and farmland), usually owned by royalty for hunting or as habitat for game animals.  

Although woodland also refers to land covered with trees, people often use the word forest to denote that a wooded area is very large, however the terms can be and often are interchangeable. 

Why are urban forests important? 

84% of people in the UK live in urban areas. 

To ensure that the majority of our population can access the benefits of nature, we must regard trees and shrubs in towns and cities of equal significance to those planted in rural areas.  

Tree canopy cover in England's towns and cities is on average, 16% but in some areas it is as low as 3%. The Woodland Trust found that despite seeing a gradual increase in UK woodland cover, much of this is non-native trees and woodland wildlife is still decreasing.  

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Planters with artwork commissioned by Bobzilla, under the Tyne Bridge.

People are innately connected to nature and access to ‘natural’ spaces is important for our health and wellbeing but access is often inequitable and can be difficult.  

57% of British adults live within a five minute walk of green space but only 39% of people from a Black, Asian or Minority Ethnic (BAME) background live within the same proximity. 

A similar trend can be seen in regards to income. Just 46% of British adults with a household income of under £15,000 live within a five minute walk of green space compared to 63% of those with a household income over £35,000 and 70% over £70,000. 

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Houses on a street lined with trees

What is the urban heat island effect? 

The urban heat island effect is a name for when urban areas such as cities experience higher air temperatures compared to nearby countryside.

Factors that contribute to this are:

  • the design and layout of buildings such as narrow streets lined with tall buildings, can reduce the flow of air at ground level
  • natural surfaces like trees, ponds, and soil reduce heat through evaporation but these are often displaced due to urban development
  • trees and other vegetation provide natural shade which lowers surface temperatures
  • man made surfaces such as tarmac absorb and re-emit heat which makes their surroundings warmer 
  • human activities and machines used by people e.g. cars and air conditioners often emit heat when they are running

The benefits of urban forests 

Protecting local green spaces and making them accessible for public use is important for the economy as well as the health and wellbeing of society. Urban forests have a range of benefits:

Reducing pollution  

  • Trees remove carbon dioxide, carbon monoxide, ammonia and sulphur dioxide from the air 

  • Trees can cut outdoor and indoor pollution by 50% 

  • Trees help to reduce noise pollution in urban areas by creating barriers that reduces travelling sound 

Climate change resilience  

  • Trees help regulate the temperature of houses in summer and in winter e.g. the urban forest in London provides £260,600 building energy savings per year 

  • In cities trees provide shade and cooling effects which help to relieve the urban heat island effect, reducing heat exhaustion, respiratory problems, and heat strokes

  • Urban areas are more susceptible to the damaging effects of rainfall and flooding 

  • Trees help to diminish the impact of heavy rain and floodwater, slows water run-off and supports the effectiveness of urban drainage systems  

  • Interception by leaves and stems can reduce the amount of rainfall reaching the ground by as much 45% 

Wildlife 

  • Urban greenspace is vital for supporting wildlife as it provides places to feed shelter and breed in addition to food sources 

Local economies  

  • Trees and woodland ecosystems in urban areas boost local economies 

  • Broadleaved trees can increase property values up to 18% 

  • Industrial areas and employment sites with access to natural greenspace can have more productive employees and tend to have greater job satisfaction   

  • Customers are found to spend more time and money in retail areas with trees compared to those without 

Health and wellbeing  

  • Trees reduce stress and encourage people to spend time outdoor and exercise 

  • Symptoms of anxiety, depression and insomnia can be relieved by spending more time in nature  

  • Cleaner air leads to reduced levels of asthma  

  • Appealing green spaces have been found to encourage people to exercise outdoors and has the ability to counteract negative health impacts such as heart disease and type 2 diabetes 

  • Green urban areas create a heightened pride of place and greater community cohesion  

Education  

  • Learning outside of the classroom is easier and more inspiring with trees to witness 

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 A view up the Avon Gorge of the Clifton Suspension Bridge with a hot air balloon launch behind

Threats to urban forests 

Urban ecosystems are complex and face many challenges, such as population growth and demand for competing land uses such as agriculture and urban development.  

As trees and plants within urban forests are living in places where humans control growing conditions and plant distribution, growing conditions can be more difficult for plants to thrive in compared to their natural environments. 

Fungal diseases are also a major threat to trees such as Horse Chestnuts and Ash trees. Learn more about Ash dieback using the resources below:

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Ash dieback

| By Isabel Negri and and Owen Blake
Blog

Hunting for healthy ash trees

| By Isabel Negri and and Owen Blake

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