Background The importance of vegetation in the fight against climate change deserves more attention. In one year, a 20-year-old tree absorbs the CO2 emitted by a vehicle travelling more than 10 000 km. On the other side of the equation, it is estimated that 1 ha of forest produces the same amount of oxygen as is consumed by six people. More plants and trees could therefore absorb more of the CO2 emitted daily by human activities. Unfortunately, urban green areas are coming under increasing pressure. In most cities, urbanisation, the construction of new infrastructure or changes in urban land management have failed to fully respect the needs of green urban spaces and trees in particular. Some trees have suffered excessive pruning, while others have simply been cut down. Land use management and urban planning need to take account of the need for urban green spaces. At the same time, trees need careful management to avoid other and different potential negative environmental impacts, which might include excessive water consumption or the spread of disease. Objectives The JEREZ+ NATURAL project aimed to create a new and innovative management model for urban trees in the southern Spanish city of Jerez de la Frontera. It thus aimed to make a valuable contribution to both improving the air quality and quality of life in the city, and mitigating climate change. The project intended to develop tools and processes for the effective management of trees and green areas at every stage, including planning, maintenance, monitoring and follow-up assessment. Its plans included development of a specific IT tool to simplify the task of carrying out inventories of species and specimens to facilitate management interventions and follow-up. The team also planned to apply: environmentally friendly treatments for the control of pest infestations and disease among urban trees in the municipality; and innovative tree-regeneration techniques for endangered species. Another key feature of the project design were participation and information processes to raise awareness of the importance of urban green areas. Through integrating the management model into the city’s urban planning, the project was expected to deliver a significant improvement of the city’s green areas and its trees in particular. This in turn was expected to achieve a general improvement of the air quality in the city, temperature moderation, noise abatement, climate change mitigation and an increase in urban biodiversity. Results The JEREZ+NATURAL project successfully demonstrated the establishment and implementation of a new management model for green urban areas. It specifically implemented a new framework procedure for the management of urban trees and integrated the management of green areas into overall urban planning processes. The project identified and geo-referenced 90 488 trees of 189 different species in the municipality of Jerez. This inventory found that many trees that appeared in earlier records had been cut or replaced by other species. An important lesson was that aerial photographs cannot be used to accurately identify individual trees. More than 80 students helped complete the inventory on the ground. Detailed information based on 38 parameters was collected on 50 180 trees. These covered: identification data (11 parameters); location details (5); environment data (6); dendrometric data (8); and risk parameters (8). Of these trees, 112 were classified as important due to one or more particular characteristics, such as age, size, height or rarity. This preparatory work helped the project establish its new management model based on a telematic tool (GIS+software) for managing and preserving urban trees. The tool takes into account all the processes affecting the trees as ‘urban heritage’, from the planting and selection of species, through conservation and maintenance works, cultural practices and the characteristics of the urban environment. The model included the successful establishment of new interdepartmental coordination processes for the management of urban trees, involving environmental, parks and gardens, infrastructures, urban planning and tourism departments. Citizens were also actively engaged through various communications materials and the creation of three ‘tree heritage walking routes’, taking in 149 species and 36 of the individually important trees. After training was provided to relevant technicians, the project demonstrated practical application of the new management model over 2 969 hectares. Interventions included the innovative application of biological treatments against pests - whitefly, aphids, pine processionary moth and red weevil - on 13 610 urban trees (four species). These treatments were based on the introduction of predatory insects. The new management model and biological treatments proved to be viable for large-scale application. They created an annual saving of 178 000 litres of water and 540 litres of commercial pesticides, representing a 95 t reduction in CO2 emissions. Sustainability of the actions was ensured by a new Bylaw approved by the Municipality, which provides a legal framework for implementation of the project’s model. Furthermore, the management system developed by JEREZ + NATURAL can easily be transferred to other cities all around the world, as well to other environmental areas (waste management, street lighting, and urban pests management, etc.). Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).