Local Authority Maintained Trees

Created 4 years ago, updated 6 months ago

We set ourselves the challenge of collating London’s tree data into one open source place to get a picture of London’s trees. We requested tree data from London boroughs and TfL in late 2014. The data mainly covers street trees, although it also includes some park trees, and contains location and species information for over 700,000 trees. It is estimated that there are around eight million trees in London, so this information is only a partial illustration of the species and location of trees in London.

There are several potential benefits to the public sharing of tree data. We hope that visualising tree data and providing access to it in one place will help to raise the public profile of the important contribution of trees to our urban environment and also provide operational benefits for tree managers. Sharing and standardising data could provide essential information for the strategic management of the urban forest. For example, it could help to assess species diversity and threats from pests and plant diseases across London and also help identify areas for additional planting. 

We note that the process of collating and cleaning the tree data we received in 2014-15 has been complex and lengthy due to the variety of systems and formats in place for recording tree data. A more standardised method of recording data for trees in the public realm could improve this in the future.

Notes on the data:

  • Data was not received from six boroughs. One other borough did not record location data in a form that was possible to easily map and so those trees could not be included. We aim to add any additional data received to the Datastore and online map.
  • Whilst the data was provided in 2014-15 the trees will have been surveyed some time before this and so some records may be several years old. 
  • The data received varied significantly by borough. Some boroughs have only included trees on highways, whilst others have included trees on housing land, in schools or in parks. In some cases trees were recorded only when work was carried out.
  • There is not a consistent or agreed format for collecting or recording tree data across London. This presents a challenge in collating data across multiple boroughs. Many boroughs collect a range of information about their trees (e.g. age, height). However this varied by borough in terms of the information collected and categorisations used so that the GLA was not able to standardise this information.
  • The GLA requested tree species information as common names. Five boroughs only had Latin names recorded. The common names given also varied widely in terms of consistency of names, spelling, etc. As such, the GLA has gone through the data and standardised the names to come up with a simplified common name for display on the tree webmap (e. g. “Pear”). These are the common names for the 22 types of tree appearing most frequently in the data (which encompass 90% of all trees), with the remaining trees categorised as “Other”. We have also left the species name as provided by the borough in the data. In total over 2,000 different species of tree were recorded, grouped into over 100 types of tree using the common names.
  • The ‘tree ID’ number has been added to the data to help map it. This number is not linked to borough’s tree management systems. Although for future data updates it would be helpful to establish such a link. 

Click on the image below to view the data mapped.



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