And it's good for the planet, too: the trees absorbed carbon when they were growing up, and they gave off oxygen, and now that carbon is trapped inside the walls and it's not being released into the atmosphere.
E é bom para o planeta, também: as árvores absorveram carbono quando estavam a crescer, e libertaram oxigénio, e agora esse carbono está aprisionado nas paredes e não está a ser libertado para a atmosfera.