The UNECE Trees in Cities Challenge, a global effort to enhance urban greening, reduce extreme heat events and improve air quality, has reached a significant milestone. Since its launch in 2019, the initiative has facilitated the planting of 18.5 million trees in cities worldwide, more than double its initial target. This significant accomplishment represents a collective effort by partners to improve our planet's well-being.  

The Trees in Cities Challenge aims to address the pressing challenges of climate change and urban pollution by encouraging the planting and care of trees in urban environments. Trees play a vital role in mitigating greenhouse gas emissions, improving air quality, reducing noise pollution, and enhancing community well-being and biodiversity. The Challenge has garnered widespread support from cities, governments, and civil society organizations around the world.  

The participation of over 80 cities in the UNECE Trees in Cities Challenge demonstrates their strong commitment to environmental stewardship and a greener future. It has inspired numerous local and regional tree-planting campaigns and initiatives.  

The planting of over 18 million trees under the UNECE Trees in Cities Challenge is a significant achievement contributing to global efforts to combat climate change highlighting also the importance of local action for sustainable development on a large scale. 

The Trees in Cities Challenge has evolved into a worldwide initiative leading to the development of dedicated support programmes and new focus areas at UNECE. These include an Urban Expert Network with over 1,000 participants, a dedicated UN Petite Forest program, urban-to-national policy action work (resulting in the San Marino Urban Forestry Action Plan), urban food trees and forests, and more recently, the Coalition for Trees in Dry Cities.  

The success of this UNECE initiative is a direct result of its strong partnerships with cities. This focus on sustainable local action for national and global impact reaffirms the organization's commitment to environmental sustainability as it plans for future initiatives. 

Find out more about UNECE’s green cities initiatives and resources:  

• Informal Expert Network on Urban Nature 

• Trees in Dry Cities Coalition 

• UNECE Tree Policy and Action Lab 

• Policy brief: Sustainable Urban and Peri-urban Forestry