Mapping Urban Forests

Urban trees are not just ornaments for beautifying streets. They contribute to an often overlooked yet valuable network of urban forests that provide a myriad of ecosystem services, create pockets of refuge for urban biodiversity, and improve the physical and mental wellbeing of city-dwellers.

I recently attended an online lecture by Dr Phil Wilkes (UCL Geography; National Centre of Earth Observation), who shared how terrestrial LiDAR technology is harnessed alongside aerial and satellite imagery to plot the range and connectivity of London's urban forests.

Screenshot of online lecture by Dr Phil Wilkes on methods of mapping London's urban forests (Source: Phil Wilkes)

LiDAR image of a chestnut tree at Kew (Source: Phil Wilkes)

LiDAR releases laser pulses which produce high-resolution 3D images of trees, allowing researchers to identify the species and phenological characteristics of individual trees. Complementing this data with airborne remote sensing allowed Dr Wilkes to estimate the aboveground urban biomass of Camden and plot the extent of canopy cover across London. These applications are pertinent in guiding pioneering research on the efficacy of urban forests as carbon sinks given the rapid expansion of urban cover over natural forests. This research would also empower more targeted management of urban forests by identifying areas where planting more trees would be most ecologically sensible for improving overall forest connectivity.

Extent of canopy cover in London (Source: Phil Wilkes)

There were two aspects of the lecture that surprised me. One was the importance of people's back gardens as bridges linking isolated patches of urban forests to enhance overall forest resilience. This highlights the potential of community engagement to encourage 'wilder' back gardens. Another was the evident inequalities in greenspace access across London - with less affluent areas being deprived of urban vegetation and possibly experiencing disproportionate effects of urban pollution.

People's back gardens (in red) as bridges linking patches of core forest (in green) (Source: Phil Wilkes)

This lecture has inspired me to explore these two areas in future posts so stay tuned!

Find out more about Dr Wilkes' work here or watch this interview with his colleague Prof Mathias Disney on the value of urban forests.

Interview: Prof Matthias Disney on the value of urban forests (Source: Dark Matter Labs)