A team of researchers has developed a revolutionary method to measure vertical heights across Catalonia, identifying the region's tallest tree in Girona. Using LIDAR (Light Detection and Ranging) technology, the system can precisely measure trees, buildings, and other landscape features, tracking their changes over time.
The new approach, developed by the Autonomous University of Barcelona (UAB) and CREAF (Centre for Ecological Research and Forestry Applications), offers unprecedented accuracy and scale. It measures areas as small as two by two metres, a resolution previously unavailable for large surfaces. Data is collected via LIDAR sensors during flights by the Cartographic and Geological Institute of Catalonia, generating dense point clouds that map the vertical shape of the territory in great detail.
Previously, transforming this vast amount of information into useful models for territorial management was too complex. Now, researchers have refined this process, correcting errors and distortions caused by interferences like birds in flight. The precision is so high that it led to the discovery of Catalonia's tallest known tree.
New Insights into Forest Growth
Xavier Pons, the project's lead investigator, highlighted the forestry applications of the results. He told reporters, "This system will allow us to analyse, with each flight, the growth rate of species and monitor the evolution of available timber volume, or relate these changes to historical fire series." Having this detailed vertical dimension helps to better understand the real texture of the landscape. "We are not only analysing forests, but also meadows and scrubland, which will likely become future forests," Pons added.
The most striking conclusion from the initial data is the detection of what is currently the tallest tree in Catalonia. It is a plane tree in Girona's Devesa Park, which measured 54.55 metres in 2021, an height comparable to an 18-storey building.
Beyond individual trees, the study analysed forest masses by region. The Aran Valley, for example, has the tallest tree stands, averaging 13 metres, followed by Pla de l'Estany and Ripollès. As expected, firs and beeches are the fastest-growing species. The new method confirms existing knowledge: Catalonia's tree cover is increasing, and its height is growing. "We are growing vertically," Pons summarised.
Urban Vertical Development Mapped
In addition to natural environments, urban areas have also been measured. In Barcelona, for instance, neighbourhoods with the highest average heights are concentrated in the Eixample. However, researchers noted significant vertical development in the Gothic Quarter, El Raval, and Sant Pere, Santa Caterina i la Ribera. Maximum heights exceed 100 metres in areas with emblematic constructions, such as the Collserola Tower, Hotel Arts, Jaume I Tower, Meliá Barcelona Sky hotel tower, or the Sagrada Família.
All the collected information will be open access, available for download and consultation. The UAB now possesses a kind of digital twin of Catalonia, focused on this upward third dimension. This model will allow for more rigorous study, with unprecedented precision, of vertical evolution in both natural and urbanised environments.
