The main street of suburban Vallecas outside Madrid is slated for a facelift. The city council decided it needed more greenery and more social activity in the street, and so they launched a competition a few years back to find a team who could creatively fill both voids. Up to the task stepped a young architecture firm called [ecosistemaurbano], whose core values center around ecological sensitivity and sustainability.

Their winning competition entry is called Ecoboulevard -- a title that encapsulates the design's fusion of industrial and natural elements. The plan is to construct three cylindrical spaces they call "air trees" using recycled gasworks, creating, as a feature on the project in Domus states:

...a sort of linear wood at the centre of the boulevard – a green belt of compact vegetation to be grown in the next 15 to 20 years...These constructions will act as focal points for the social life of the new urban settlement, which to date has no public meeting places. At the base of the three so-called “air trees,� each with a diameter of about 20 metres, a slight hollow will accommodate the normal activities of an urban park.

One of the air trees will be planted with greenery inside and out, the other just inside, and the third will be foliage on the outside, but the inside will instead house a giant screen, turning this into a literal theater-in-the-round for the community. All of the infrastructure placed in the boulevard will be energetically self-sufficient, relying only on solar panels for its electrical needs. Cooling of the interiors will be done through an evaporation and transpiration method using pumped water and the walls of plants to reduce the temperature.

[ecosistemaurbano] states on their website that all of their work pays careful mind to the end-of-life scenario, and to a choice of materials that can be easily disassembled. From this principle emerges perhaps the coolest aspect of the Ecoboulevard project: once the plants have established themselves around the gasworks structures, those components will be dismantled and taken away, leaving behind a triad of forest clearings in the center of the road.