Climate risks are unevenly distributed, both within and between cities. Cities with outdated infrastructure, urban sprawl, inadequate housing regulations and supply, are at particularly high risk. Building urban resilience to climate change is a complex, multi- stakeholder driven process, and is often constrained by the lack of resources.
In this context, nature-based solutions are both cost-effective and scalable. They simulta- neously mitigate climate change and contribute to building resilience against climate- related and natural hazards. Urban and peri-urban trees and forests are one such solution.

Strategic, tailored and ambitious tree-planting and strengthening capacities for sustainable management of urban forests is a palpable way for local governments to contribute to climate action and the Sustainable Development Goals (SDGs).

As we enter the UN Decade on Ecosystem Restoration, hoping to inspire large-scale efforts to halt the destruction of natural habitats and restore degraded ecosystems, this is the perfect moment for city governments to step in and contribute.

In 2019, the United Nations Economic Commission for Europe (UNECE) launched the “Trees in Cities Challenge”. This initiative invites mayors and local governments worldwide to make a concrete tree-planting pledge that will be implemented within a year and set up their objectives for making their cities greener, resilient, and more sustainable. The “Trees in Cities Challenge” will last until the end of 2022.

Mayors and local authorities pledging under the “Trees in Cities Challenge” are invited to become part of a global community of change-makers and offer their residents benefits from the many ecosystem services that trees and forests in and around cities provide.

For more information, please visit treesincities.unece.org

The main concern of this project is the cost-effective use and promotion of the climate-adaptive ecosystem services that urban trees and forests offer as an existing resource. This outstanding importance is still too little recognised in Switzerland and insufficiently integrated in strategic as well as operational planning. With the open source application i‑Tree, structural and quantitative strengths and deficits can be identified on a science-based basis. The project enables the combination of this information with interdisciplinary strategies and applications, allowing creative solutions to be developed to improve the climate-adaptive benefits of urban trees and forests. This project will improve the ability of Swiss cities to provide large canopy volumes in the long term, to plan locally in a concrete way and to manage them sustainably, as vital, large canopies are especially important for providing ecosystem services to ensure climate-adaptive management of green resources.  

Further information

In the ReBio project, we will identify knowledge gaps and based on these we will develop a research agenda for future Biocities. The research agenda will be developed by considering urban forests from different perspectives (e.g. social, economic, ecologic). These perspectives will allow us to identify synergies, trade-offs and knowledge gaps within and between diverse aspects of Biocities, enabling us to develop an innovative Research Agenda that meets the current needs of cities and proposes solutions for existing challenges.