Citizen Science Seminar: Assessing Urban Carbon Sequestration: Tree-Quest, a Citizen Science Mobile App to Measure Single Trees

Overview

Trees play an important role in absorbing atmospheric carbon and storing it as they grow. However, information on the size, condition and characteristics of urban trees is often incomplete or outdated. While many European cities maintain tree inventories, these are not always regularly updated, and many cities have no comprehensive inventories at all. This creates challenges for accurately assessing and monitoring the carbon stored in urban trees.

Tree-Quest is a free citizen-science mobile app developed to help address this data gap by enabling people to collect measurements of individual trees. By generating large amounts of open ground-based data, the app has the potential to complement traditional tree inventories and provide information at spatial and temporal scales. At the same time, Tree-Quest gives citizens an opportunity to learn more about the trees around them and their role in the global carbon cycle.

As part of the Citizen Science Seminar series organized by Österreich forscht, Milutin Milenković has been invited to present the Tree-Quest. This seminar will introduce the Tree-Quest app and present the results of its 2026 pilot campaign in Austria. More than 35 Austrian school classes participated in the campaign, collecting over 30,000 measurements of local trees. The presentation will also cover current efforts to quality-check and curate the collected data, combining manual approaches with AI-based methods, with the aim of making the resulting dataset openly available.

About the speaker

Milutin Milenković is a Research Scholar in the Novel Data Ecosystems for Sustainability Research Group at IIASA. His research focuses on combining Earth Observation and Citizen Science to monitor environmental change, particularly forest growth and resilience. He holds a PhD in Photogrammetry and Remote Sensing from the Vienna University of Technology and is also a guest lecturer there.

The seminar is open to both students and the general public
Places for are limited and registration is open until 16 November 2026.

Read more and register here.