Andalusia and the Canary Islands are cooperating over low heat. Heat waves are increasingly frequent and urban asphalt accumulates and returns heat as a burning iron. In the midst of this suffocating panorama, a Spanish research team strives to Select the best plants to lower cities temperature South: the current one and the one that is predicted for the next few years. After analyzing for several months more than three hundred plants, the Royal Botanical Garden (RJB) of the Higher Council for Scientific Research (CSIC) has completed a list with 182 species.
These specimens will be included in the Paulia project, a program that seeks to combat the phenomenon of the heat islands in urban areas of warm climates in the Canary Islands and Andalusia. Led by the Technological and Renewable Energy Institute (Iter), it also has the collaboration of the Eduardo Torroja Eduardo Torroja (IETCC-CSIC) and the municipal services of Granadilla de Abona, in Tenerife. Its objective: refresh cities through a Strategic combination of plants and construction materials.
«What we intend is Improve urban thermal comfort Selecting plants that resist warm, present and future climates, taking into account the planned increase in temperatures, ”explains Laura Santamaría, a researcher at the RJB-CSIC. His team has developed the catalog prioritizing criteria such as drought resistance, their safety in public spaces (which do not bear large fruits or have low allergenicity), their aesthetic quality and, above all, positive impact on temperature. «Plants help by two key paths: the shadowwhich prevents the sun from directly the ground, and perspirationthat refreshes the environment by releasing water vapor from the leaves, ”says Santamaría. “According to recent studies, a well -located tree can reduce the temperature of an asphalt pavement up to 10 degrees,” he says.
Among the selected species to be applied in the cities of the South, some stand out as well known as The vine (Vitis Vinifera), for its ability to climb and provide shadow in the form of a parra and that could be ideal in both the Canary Islands and the Peninsula. Others, such as the Sedum, a succulent that forms “carpets” to protect the soil from heat and erosion. In the trees category, Almez (Celtis Australis) and La Jacaranda, a South American exotic With purple flowers and wide cup, they have earned a place for their lush, aesthetics and efficiency. However, the vast majority of selected species are native.
The project does not stay in a list, but will germinate on an advisory digital platform. This tool will serve to Town Halls and Urbanists choose the most appropriate vegetation and materials For their spaces. “We want it to be practical, with chips and data on morphology, phenology, availability in nurseries and other criteria,” adds the researcher.
But Paulia does not stay green. Carmen Alonso, researcher at the Research Group Construction Systems and Habitability of the IETCC-CSIC, recalls that “the materials also count.” Its part of the project focuses on facades, pavements and buildings of buildings: how they absorb, reflect or reign heat. «We use physical models and algorithms to predict what would happen if we change materials In a city. There are cold paintings, photocatalytic and thermochromic materials, which change color with temperature. The objective is to create an intelligent urban design, ”he explains.
In it Tenerife municipality of San Isidro, Paulia is already applied in practice. Critical heat areas have been identified and combinations of vegetation and materials will be tested to validate the tool, which can later be extended to other towns in southern Spain. The integral approach to the project becomes a necessary proposal. As Alonso summarizes: «It is an advisory tool, but also an opportunity to change the way we design our cities. It is not only about cooling the asphalt, but also making them more habitable ».
The Paulia project has the support of the State Agency for the Ministry of Science, Innovation and Universities, through the call for aid to public-private collaboration projects, the State Plan for Scientific, Technical and Innovation Research Plan 2021-2023, within the framework of the Recovery, Transformation and Resilience (PRTR) plan.