The street trees have really four jobs to do and that's it: To spatially denote the pedestrian realm, to protect the pedestrians from the vehicles in the carriageway, to filter the sunlight onto the sidewalk, and to soften the hardscape of the buildings and to create a ceiling — a vaulted ceiling — over the street, at its best. And that's it. Those are the four jobs of the street trees.
Delimitan espacialmente el ámbito peatonal, protegiendo a los peatones de los vehículos en la vía, filtran los rayos de sol que alcancen la acera, y suavizan la dureza de los edificios y crean un techo — un techo abovedado — sobre la calle. Eso es todo. Esas son las cuatro funciones de la arborización callejera.