We collect data on the city’s trees using Ezytreev™ tree management software as part of our routine inspections. We also continue to commission analyses of tree data in the city to help us understand the structure, composition and value of the city’s urban forest.

We are working toward making our data more open. The tree data on this page contains data that is commonly sought as part of Freedom of Information requests and other data that puts the city’s tree cover into a wider context.

Number of trees in Cambridge

It is difficult to know exactly how many trees there are in Cambridge at any one time. Estimates vary depending on the techniques used to gather the information.

The latest estimates using data Proximitree™ data is that there are 335,000 trees and shrubs over 1.2m in height. However, tree canopy cover is generally considered to be a better metric of the health of the urban forest than tree numbers.

Source: Tree canopy cover in Cambridge between 2008 and 2018 (Dr T Jackson, 2023) [PDF, 3MB].

10 most common types of tree in Cambridge

The data below is derived from our own tree inventory and randomised sample plot across the city as a whole, regardless of ownership. Good species diversity is another metric of the health of the urban forest.

Source: Analysis and interpretation of tree audit data for Cambridge City Council (ADAS, 2013) [PDF, 6.5MB].

Council parks and street trees

• Cherry (Prunus): 14%
• Maple (Acer): 12%
• Lime (Tilia): 8%
• Birch (Betula): 8%
• Sorbus (Sorbus): 8%
• Ash (Fraxinus): 6%
• Apple (Malus): 4%
• Thorn (Crateagus)
• Willow (Salix): 3%
• Horse chestnut (Aesculus): 2%

Cambridge city as a whole

• Ash (Fraxinus): 22%
• Cherry (Prunus): 15%
• Lime (Tilia): 8%
• Apple (Malus): 6%
• Cupressus (Cupressus): 6%
• Sorbus (Sorbus): 5%
• Maple (Acer): 5%
• Birch (Betula): 5%
• Yew (Taxus): 4%
• Poplar (Populus): 3%

Tree canopy cover

Tree canopy cover is the metric used to indicate the benefits provided by the urban forest, and is measured as a tree canopy cover percentage of the total area under review.

In 2018, tree canopy cover was measured at 17.6% by analysing Proximitree™ data. This is a slight improvement of 0.5% representing an increase of 20 hectares over 10 years. Ward measurements were:

• Abbey: 14.3%
• Arbury: 18.4%
• Castle: 18.4%
• Cherry Hinton: 13.1%
• Coleridge: 17.4%
• East Chesterton: 19%
• King’s Hedges: 17.5%
• Market: 16%
• Newnham: 21.2%
• Petersfield: 17.3%
• Queen Edith’s: 17.9%
• Romsey: 17.5%
• Trumpington: 18.1%
• West Chesterton: 21.1%

Source: Tree canopy cover in Cambridge between 2008 and 2018 (Dr T Jackson, 2023) [PDF, 3MB].

Cambridge’s tree canopy cover compared with other districts

The amount of tree canopy cover depends on a number of different factors including population and built density, land use type, and age of primary development.

We have selected a list of four towns and cities of similar size, populations and land uses. Cambridge fairs pretty well in these comparisons. The same methods have been used for measuring each of the factors for each of the towns to allow for more accurate comparisons.

Sources:

• Population: List of English districts by population – last accessed 21 May 2019
• Population density: List of English districts by population density – last accessed 21 May 2019
• Land use: How much is your area built on (BBC) – last accessed 21 May 2019
• Tree cover: Doick, K., et al., (2017) The Canopy Cover of England’s Towns and Cities: baselining and setting targets to improve human health and well-being

Ownership of tree cover in Cambridge

The bulk of tree canopy cover in Cambridge is in private ownership. Most of this is in residential gardens which make up the largest single land use (around 39%):

Source: Tree canopy cover in Cambridge between 2008 and 2018 (Dr T Jackson, 2023) [PDF, 3MB].

Number of trees felled each year

The figures below relate to individual street and parks trees only. Figures are from 2009 to 2023. The data is recorded by our tree officers using Ezytreev™ tree management software. It should be treated as indicative as it does not show for example trees in groups or recently planted trees that have been removed within the first year of planting:

• Find out more about how we manage trees in Cambridge

Number of trees planted each year in streets and parks

The figures below relate to planting ‘standard’ trees that are between 2.5 & 3.5m tall at planting, and planted in our streets and parks trees only.

The data is recorded by our tree officers using Ezytreev™ tree management software. In 2016 we approved a ring-fenced budget for tree planting that meant we can ensure no-net-loss to our tree population.

Between 2019 and 2023 we were a partner in the Nature Smart Cities across the 2Seas green infrastructure which funded the planting of over 2000 trees as part of it’s green infrastructure pilot, the Cambridge Canopy Project.

• Request a tree to be planted in a street or park

The Free Tree for Babies scheme

This has been running for over 30 years to incentivise tree planting in the city. In 2017 we approved a ring-fenced budget for the scheme of £5000. In 2018 we changed the way we delivered the scheme enabling us to increase the amount of trees could give away under the scheme.

• Find out more about our Free Tree for Babies Scheme

Ash decline in Cambridge

Ash trees have been estimated to make up around 22% of the total number of trees in Cambridge.

They are currently under threat from Ash Dieback Disease which is predicted to kill around 95% of all ash trees in the UK. Ash Dieback has been officially recorded as being present in the Cambridge area since 2014.

We have over 1400 individual ash recorded on our tree management database (excluding groups & woodlands). The following ash species where present in May 2018:

• Fraxinus americana: 1.2%
• Fraxinus angustifolia: 0.4%
• Fraxinus excelsior: 77.4%
• Fraxinus excelsior ‘Diversifolia’: 1.7%
• Fraxinus excelsior ‘Jaspidea’: 1.1%
• Fraxinus excelsior ‘Pendula’: 0.6%
• Fraxinus excelsior cultivar: 0.1%
• Fraxinus ornus: 6.5%
• Fraxinus oxycarpa: 0.1%
• Fraxinus oxycarpa ‘Raywood’: 6.7%
• Fraxinus pennsylvanica: 0.2%
• Fraxinus (not identified to species level): 4.0%

A randomised sample of 99 trees from this population was taken in 2017 and surveyed in September of that year. The aim is not aimed to identify ash die back disease but to monitor ash condition as indicative of the spread and effect of the disease.

Follow-up surveys have been undertaken annually except in 2020 and 2022. A new survey is planned for 2023. The survey measured the amount of defoliation, deadwood and regrowth present in each tree and the results are presented below.

The degree of defoliation from the norm is indicative of the degree of stress a tree is currently under.

The amount of regrowth is both indicative of stress and the ability of a tree to respond to that stress:

The size of the deadwood is indicative of the overall effect that stress is causing the tree:

• Download the survey methodology [PDF, 0.4MB]

Number of TPOs served each year

The Council has served over 800 TPOs since 1955. The table below shows the numbers served since 2009:

Number of tree work applications assessed each year

Applications and notifications of works to tree protected by TPO or that grow in conservation areas have to be submitted to us for assessment:

• Find out more about protected trees

Number of high-hedge complaints received each year

Under the Anti-Social Behaviour Act 2003 local authorities must deal with disputes between neighbours regarding high hedges, where a complaint has been made under the Act.

• How to make a High Hedges complaint

2023 tree data report: significant findings

• Overall canopy cover increased from 17.1% in 2008 to 17.6% in 2018. This increase was mostly due to the growth of medium and large trees, since young trees have smaller crowns.
• The only wards to experience a decrease in canopy cover were Castle, due to the large construction projects, and Newnham, because of a substantial decrease in canopy cover in gardens. Nevertheless, Newnham remained the ward with highest canopy cover in 2018.
• Gardens account for a high proportion of canopy cover, given their relatively small area. The area of land dedicated to gardens decreased in all wards between 2008 and 2018 due to densification. However, in some wards, the canopy cover in these gardens increased. This suggests that gardens are a potential target for tree planting or preservation.
• Tree preservation orders are currently located mostly in the wards with high canopy cover, so targeting wards with lower canopy cover would be valuable.
• Protected open spaces contain a high proportion of tree canopy cover, particularly for large and massive trees in those wards with lower total canopy cover. Therefore, protected open spaces are important for protecting and increasing tree canopy cover in the areas of Cambridge which need it most.
• Between 2008 and 2018, canopy cover increased substantially in most parts of Cambridge with a high index of multiple deprivation. These areas now have canopy cover comparable to the rest of the city. To increase this further, efforts should focus on adding new tree preservation orders.
• Source: Tree canopy cover in Cambridge between 2008 and 2018 (Dr T Jackson, 2023) [PDF, 3MB].

Mapping tree shade in Cambridge

In summer, Cambridge can be one of the hottest places in the UK. The shade provided by urban trees is valuable, especially to pedestrians and cyclists. Increasing this tree-shade can improve people’s wellbeing and encourage more active travel.

We commissioned a report to map tree shade in the city – it assessed shade at 8am, midday and 4pm. It also looked at opportunities to plant trees on public land and in adjacent private gardens. It recommends concentrating tree planting and protection efforts in areas with lower levels of tree-shade.

• Mapping tree shade in Cambridge (Dr T Jackson) [PDF, 2.5MB]

Significant findings

• Shade varies through the day. Most streets in Cambridge have more than 50% shade at 8am, while many have less than 20% shade at midday.
• West Cambridge, particularly Castle and Newnham, has the highest level of shade.
• The variation in shade level is greatest at 4pm. At this time, many streets have low levels of shade but with planning it is possible to find shaded routes through the city. Because of this, we plan to use the 4pm shade map to prioritise streets for new planting.
• The streets with least shade include Castle Street, Daisy Close, Frank’s Lane, Hatherdene Close and Kilmaine Close.
• Road shade is not related to the proportion of the road bordered by gardens. This could signify an opportunity to increase tree planting and protection in private gardens to increase road shade. It could also be a methodological issue, as we focused on gardens and did not include parks and other green spaces.
• Roads with more council-managed street trees had higher levels of shade. This suggests that our management of these trees has increased the shade on these roads. Future protection of street trees should increase it further.

Tree equity score

Some urban areas have a lot of tree cover, while others lack these essential natural assets. Tree equity is the idea that all communities should have equitable access to the benefits of trees where they live.

A tool called Tree Equity Score UK launched in 2023. It generates scores from 0 to 100 for most urban neighbourhoods, and composite scores based on them for local authorities.

The tool uses tree-canopy data from Google and six climate, health and socioeconomic indicators to calculate its scores. It shows that, in areas of lower tree cover, there is a direct link to more pollution and poorer air quality.

Composite scores ranged from 61 to 96 across the 327 local authorities that were assessed. The score for Cambridge was 91, putting us in the top 19% of local authorities for this score. 45 other local authorities scored 91 or more.

The tool was co-developed by American Forests, the Woodland Trust and the Centre for Sustainable Healthcare.