still rich in natural forest and wildlife, rio has been altered by human occupation - originally, the entire state of rio de janeiro was covered by vast tropical rainforests. the changes began in the 16th century, with continued urban expansion and the develop of plantations, which had a devastating effect on the environment.

 starting in the 19th century with the restoration of the forest of tijuca, many highland areas began to be reforested, and national parks were established to protect the native ecology.