While studying at the Bartlett School of Architecture in London, recent graduate Tom Noonan produced a series of variably-sized hand-drawings to illustrate a fictional reforestation of the Thames estuary. 
From Noonan’s own project description:

The reforestation of the Thames Estuary sees the transformation of a city and its environment, in a future where timber is to become the City’s main building resource. Forests and plantations established around the Thames Estuary provide the source for the world’s only truly renewable building material. The river Thames once again becomes a working river, transporting timber throughout the city.