EIR - London Tree Map [Feb 2025]

Request

I would greatly appreciate it if you could answer a few questions:

How did you map the features for the Tree Map project?
- What methods or technologies did you use for data collection in the Tree Map project?
- Did you employ any specific tools or mobile applications? (GPS or another method)?
- Which geographic information system (GIS) do you use, such as ArcGIS?
- How you maintain this collected data?

Response

What methods or technologies did you use for data collection in the Tree Map project?

The London Tree Map collates tree inventory data from London Boroughs and other major landowners who own and manage public realm trees in the capital (e.g. trees in streets, parks and other publicly accessible greenspaces).

Participation in this data collation project is voluntary. The data supplied reflects the status of each landowners’ data inventory at the time of sharing – i.e.: no specific data acquisition effort is undertaken as part of this project. This is simply a data sharing initiative.

Willing data holders send their datasets in .cvs format to Greenspace Information for Greater London (GiGL), the environmental record centre for London, which assembles and/or maintains some environmental datasets on behalf of the Greater London Authority (GLA).

GiGL undertakes basic data standardisation so as to be able to merge the tree datasets thus collated into a single, non-exhaustive, pan-London database.

Did you employ any specific tools or mobile applications? (GPS or another method)?

Neither GiGL nor the GLA assumes responsibility for the creation of the source data shown on the London Tree Map. The digitalisation of all tree records and associated tree data is carried out by each individual landowner according to their own data collection methodology standards, and timeframes. As highlighted above, no specific data acquisition effort is conducted for this project: data holders rely on the data they have at the time of sharing.

For the first release of the London Tree Map in 2014, and its partial update in 2021, data holders for London’s public realm trees were simply requested to supply, at a minimum, for each tree record:

• Location data (e.g. longitude, latitude)
• Taxonomic data (e.g. species, genus, family)

In the latest update (due to be released later this year), we have also trialled collating information on:

• Girth (e.g. tree diameter at breast height)
• Age
• Spread
• Conditions

However, as underlined above, there are currently no shared standards on how London Boroughs and other landowners managing some of London’s public realm trees collate this information.

One of the benefits of the latest iteration of this project is to:

1. Highlight disparities in data recording standards;
2. Facilitate a dialogue on the value of moving towards a shared data collection and recording protocol for some key fields, and on what such  key fields and shared standard could be.

How you maintain this collected data?

GiGL and the GLA are in the process of updating the London Tree Map.

A call for data was put out last year to all 32 London Boroughs, the City of London and other landowners managing a significant proportion of the London public realm such as Transport for London or the Royal Parks.

The resulting updated pan-London dataset will be released later this year.

This latest and upcoming version of the London Tree Map will capture a larger number of public realm trees, reflecting an increase in the number of London Boroughs and other landowners participating in the project.

Once available, information on the 2025 London Tree Map update will be available at:

London tree map | London City Hall