DTwin4City
Digital Twin for Urban Planning
Overview
Context
Extreme weather events threaten health, biodiversity and urban infrastructure. By 2050 in France, average temperatures could rise by 1.6 °C in Nice and 1.1 °C in Le Mans, with summer increases of 2.8 °C and 2.0 °C respectively. Green spaces, particularly trees, help to reduce air pollution and heat islands, promote biodiversity and improve citizens’ well-being. Increasing tree cover to 30 per cent could prevent 12,000 deaths per year across 744 European cities (Sicard et al., 2025*). The European Union (EU) is calling on towns and cities with more than 20,000 inhabitants to draw up ambitious greening plans (COM(2020)380), whilst the European Regulation on Nature Restoration (2024/1991) sets the target of no net loss of green spaces by 2030 and measurable progress from 2031 onwards. In this context, the 3-30-300 rule serves as a benchmark (see box opposite). | The 3-30-300 rule . to be able to see at least 3 trees from one’s home, workplace or school, . live in a neighbourhood with at least 30 per cent tree cover . and be within 300 metres of a public green space. |
👉 DTwin4City will develop and provide local authorities with a digital twin enabling them to assess compliance with Regulation 3-30-300, identify areas for (re)greening, simulate various planning and greening scenarios, and evaluate their benefits. Tested in Nice and Le Mans, it will be accompanied by a guide to sustainable greening plans.
Methodology
The creation of a digital twin will involve four stages: creation of a 3D data cube, modelling of green spaces, integration into a cloud platform, and development of scenarios. Environmental, climatic and urban models (e.g. FlorTree, PALM-4U, WRF/Chem) will enable the detection and classification of trees in cities, the assessment of ecosystem services, and the simulation of the effects of different (re)vegetation strategies, according to various climatic and socio-economic scenarios (Manzini et al., 2023; Sicard et al., 2023; Lopez et al., 2025; Anav et al., 2026; Torrentí et al., 2026; Sicard et al., 2026*).
Modular, interoperable and scalable, the digital twin will enable real-time simulations and long-term planning. This predictive capability is crucial for long-term urban planning and climate change adaptation strategies. Co-design workshops with local authorities will define the platform’s architecture and requirements.
Application site(s)
France: Le Mans and Nice
Data
DTwin4City offers a digital twin combining satellite data, 2D-3D data, artificial intelligence, GIS and climate scenarios.
Satellite
For each tree, precise data on its location, species and structural characteristics – such as tree height and leaf area index – are essential for quantifying ecosystem services. The spatial resolution of very high-resolution optical satellite sensors (e.g. Pléiades, WorldView-2) enables the detection, classification and mapping of tree attributes at a fine scale (Sicard et al., 2023*).
Other
The Copernicus Atmosphere Monitoring Service provides daily forecasts of EU-regulated pollutants, pollen and aerosols. The Copernicus Climate Change Service provides climate data to support the EU’s climate change adaptation and mitigation policies. These datasets (e.g. surface temperature, wind, air temperature, relative humidity, global radiation, as well as concentrations of NO₂, PM₂.₅, tropospheric ozone and CO₂) will be used as model inputs.
We will map vegetation distribution and phenology (e.g. start and end dates of the growing season) using the Copernicus High Resolution Vegetation Phenology and Productivity datasets derived from Sentinel-2 imagery at a spatial resolution of 10 m for the two pilot cities.
Results – Final product(s)
The DTwin4City tool will help local authorities assess different planning scenarios, providing an essential tool to help cities develop resilient, carbon-neutral green spaces.
🖥️ Digital twin web platform
Featuring an intuitive user interface, the demonstrator for the two pilot cities will be freely accessible for viewing data and simulations.
The DTwin4City digital twin will enable users to:
map green spaces
map compliance with the 3-30-300 rule
quantify the ecosystem services provided by green spaces and how these change over time
map areas at risk
map priority areas available for renaturation.
👉 The DTwin4City digital twin will help urban planners make informed decisions on priority areas for adding vegetation and on how this can be used as effectively as possible, for example to reduce air pollution and mitigate urban heat islands.
👥 Local authorities – in particular technical staff and managers responsible for green spaces – will be trained in the use of the digital twin. The project also includes the publication of a practical guide to support the implementation of long-term urban greening plans.
All non-confidential outputs generated as part of the project will be freely accessible on request and made available to both local authorities.
References
Anav A., Gualtieri M., D'Elia I. Paoletti E., Sicard P., De Marco A., Sorrentino B., 2026, “Leveraging peri-urban forests to reduce temperature and pollution related urban mortality". Nature Communications Earth & Environment 7, 108. https://doi.org/10.1038/s43247-025-03079-2
Torrentí F., Sicard P., Alonso L., Calatayud V., 2026, “The rule 3-30-300 for a healthier and greener compact Mediterranean city”. Journal of Environmental Management 404, 129541. https://doi.org/10.1016/j.jenvman.2026.129541
Sicard P., Pascu I-S., Khaniabadi Y.O., Calatayud V., 2026, “Urban Forest patch cover across Asia over the last decade: Call for green innovation”. Journal of Environmental Management 405, 129666.https://doi.org/10.1016/j.jenvman.2026.129666
Sicard P., Cordon T., André L., De Marco A., Paoletti E., Perez S., Leca S., Omidi Khaniabadi Y., Calatayud V., 2026, “Is compliance with the 3-30-300 rule associated with subjective citizens' well-being?”. Journal of Environmental Management 419, 131016.
Bertassello, L.E., van der Velde, M., Maes, J. et al., 2026, “Assessing European cities with the 3-30-300 rule underscores the need for enhanced urban greening efforts”. Nature Communications 17: 4846. https://doi.org/10.1038/s41467-026-71523-8
Lopez M.A., De Marco A., Anav A., Sorrentino B., Paoletti E., Manzini J., Hoshika Y., Sicard P., 2025, “The 3-30-300 Rule Compliance: A Geospatial Tool for Urban Planning”. Landscape and Urban Planning 261, 105396. https://doi.org/10.1016/j.landurbplan.2025.105396
Sicard P., Pascu I-S., Petrea S., Leca S., De Marco A., Paoletti E., Agathokleous E., Calatayud V., 2025, “Tree canopy cover and air pollution-related mortality in European cities”. The Lancet Planetary Health 9: e527-e537. https://doi.org/10.1016/S2542-5196(25)00112-3
Sicard P., Coulibaly F., Lameiro M., Araminiene V., De Marco A., et al., 2023, “Detection and Classification of Urban Trees from Very High-Resolution Satellite Imagery”. Urban Forestry & Urban Greening 81: 127866. https://doi.org/10.1016/j.ufug.2023.127866
Sicard P., Agathokleous E., Anenberg S.C., De Marco A., Paoletti E., Calatayud V., 2023, “Trends in urban air pollution over the last two decades: A global perspective”. Science of the Total Environment 858: 160064. https://doi.org/10.1016/j.scitotenv.2022.160064
Related project(s)
SCO projects
Data and models from the SCO projects GreenSpace, Green Urban Sat, SatLCZ and Target 2050 are available for the analysis of green spaces, tree detection, compliance with the 3-30-300 rule and the mapping of urban heat islands. The AirCrowd project measures air quality at low cost and models urban strategies.
Non-SCO projects
LIFE AIRFRESH “Air pollution removal by urban forests for a better human well-being”
