“Our focus is not necessarily to build a city, but rather to grow a city.” So says Chris Precht, one of the co-founders of Penda, a Beijing and Vienna-based architecture firm that has a new vision for a low-carbon future in China. What if cities were surrounded by pollution-sucking bamboo forests, and built from bamboo instead of steel?

“Bamboo is a underrated material, especially when it can be used locally,” he says. As the plant grows–as much as a foot a day–it acts like an air purifier, generating up to 35% more oxygen than a similar stand of trees, while absorbing the same amount of carbon dioxide. As it’s harvested, it automatically regrows without being replanted. And in a building, it’s two to three times stronger than a steel beam of a similar weight.

In a new design, Precht and cofounder Dayong Sun created a modular structure with X-shaped bamboo joints. Instead of nails or screws, each joint is secured with rope. If a building needs to come down–like the temporary installation the architects recently built at Beijing Design Week–it can easily be dismantled and the bamboo can be reused.

Because it’s simple to build and modular, it could also be used for disaster shelters in places that have a natural supply of bamboo. “The problem with shelters after a disaster is that you need to get the shelters transported to those regions,” says Precht. “If a region has local bamboo, just the technique of construction needs to be explained, and the shelters can be built up in a short amount of time.”

The designers also envision that it could be used to create entire cities in China, using a paired system of planting bamboo groves next to buildings. For each cane of bamboo chopped down for buildings, more could be planted in the forest, providing fresh air and a constant supply of new building material for the city.

The frames of the buildings could also double as planters for a vertical garden. “Eventually, plants become more dominant as a design element,” Precht says. “Nature takes over and architecture comes second.”

It’s a radically different model for construction that they’re hoping will spread. “All our cities are growing at a fast pace, but so is pollution,” he says. “With a population of 9 billion by 2050, will we still have fresh air to breath or clean water to drink? We need to start thinking about alternatives. Especially in the building industry, as much of the pollution is caused by it.”