London’s Street Trees on the Map (well, most of them)

Some months ago I heard rumours about a London Street Tree map being prepared by the GLA at City Hall. Excitingly, that map is now live and has been for a couple of months. For those who haven’t yet poured over the fascinating insights into what trees can be found on London’s streets would be well advised to stop reading this and get over to the map now!

Underlying the map interface there exists a vast database of information, no doubt hard won, wrestled from individual boroughs. Each borough is responsible for the trees on their patch and each has a team dedicated to their management. Perhaps not surprisingly then, each borough holds their own records for their part of the urban forest, and each borough uses different ways to gather and store this data, not to mention what data it actually harvests and holds. Therefore the feat of wrangling data from these various sources into a single dataset providing consistent information should not be underestimated – makes my brain hurt just thinking about it.

There are some black holes – for instance, Hackney and Haringey are two of seven boroughs that have yet to provide their data, but 25 of the 32 boroughs, plus the City of London and TfL have done and even with gaps, the potential of this map is becoming clear. Knowing what is planted on our streets is not only of interest to those who manage the tree inventory, this information can start to inform planning decisions, provide environmental insights and help shape policy to improve air quality. If there’s a correlation between levels of pollution and mature Plane Trees for instance, then this map could be a tool in that investigation right across the city. For me though, the most exciting possibility is the potential for public engagement.

The street tree data including location and species information is in the public domain and is released under an Open Government licence. It can therefore be used by third parties to exploit both commercially and non-commercially. And this is where the opportunities lie: imagine an app that can tell you what the tree is outside your front door, or the tree you walk past on your way to work? All possible with the data. Imagine walking up to a tree and discovering through your smart phone that it is a 150 year old Plane tree, it’s 33m tall and it’s one of 253,751 Plane trees in London, one of the most frequent trees in the city. This Plane tree stores CO2, soaks up pollution, moderates temperatures and has a financial value too. Imagine another app, this one educational, telling kids about all the minibeasts that make their home in an Oak tree outside their school or a Rowan tree on their street. It could tell them that an ancient pollarded Black Poplar tree in the local park was there long before the park and that it is a rare native tree that needs protecting. Another app could guide users on tree trails around Hampstead, Putney or wherever, it could allow the users to add comments about the trees on the trail, even add their own trail or check in at the Wembley Elm on Facebook.

And then of course there are more practical or nerdy applications, want to check out where all the Kentucky Coffee Trees are in London? Want to let your Local Authority know about the broken branch on a tree in your street? Want to see where the empty tree pits are? Want to get involved in community street tree maintenance?

So, what do other cities do about mapping street trees? New York appears to be leading the way with their recently launched map. It is worth noting that New York is in a very different position to London in that one city-wide body manages the street trees ensuring the data wrangling issues faced in London just don’t exist, so they have the luxury of focusing on visualistaion and functionality. New York’s data is real time, users can register and once logged in, favourite individual trees and get involved with community street tree activities like planting and maintenance.

Melbourne’s map, like New York’s, allows users to zoom in almost to street level, but it only covers a relatively small area of the city centre. As reported in media around the world, users can email trees in Melbourne which while possibly a bit odd has clearly caught the imagination of many.

The London Street Tree map and especially the data underpinning it are tools that could help us understand, appreciate and value the trees in London which in turn could make our lives richer and healthier. I can’t wait to see it show all the street tree data, and with more detail too – exact species info would be great to see.