CONICET | Buscador de Institutos y Recursos Humanos

The city of Mendoza, in the central-western Argentina, is characterized as an oasis-city in a desert environment.In recent decades the urban growth has increased the stress factors affecting afforestation. The water deficit and repeated drought periods cause water stress. Additionally, the heat island phenomenon stimulates thermal stress conditions. This scenario impacts the growth patterns of urban trees, its longevity and environmental benefits. It is inferred that the thermal stress, coupled with a set of factors, negatively affects the tree growth with a marked deterioration of the urban afforestation.An initial diagnosis assessed the growth under water stress conditions, now it seeks to quantify the effect of thermal stress in two representative tree-species and different urban configurations in Mendoza city. The analysis of their responses to this stressor will reveal in greater depth the vulnerability of urban trees to sustained increases in temperatures.Surface temperatures of trees and materials (roads and walls) were measured by thermographies. Mean radiant temperatures and microclimate of the spaces are recorded with fixed sensors and weather stations, in summer and winter. Annual tree growth is quantified by dendrochronological analysis in time series of at least a hundred years.The results of summer show that the foliage temperature was 1-2 °C lower than the average air temperature and surface temperatures. The comparative analysis of tree-species added to lower annual growth allow us infer that the increase of air and surfaces temperatures of urban space, causes thermal stress on trees.It is expected to categorize tree-species according to proper growth responses under thermal and water stress conditions, and to transfer these results to entities responsible for the management and planning of urban afforestation.