The petrified jungle was the remains of a forest on Skaro, in which all vegetation had been turned to stone, presumably by the use of neutron bombs in the neutronic war (or, alternatively, in the Thousand Year War). The TARDIS materialised in the jungle when it first arrived on Skaro. The First Doctor, Susan, Ian and Barbara found the body of a magnedon there. A party of Thals led by Temmosus made their camp in the jungle during their quest to save their people. (TV: The Daleks)
At some point, presumably in the 41st century, an area of the jungle was recovered from Skaro by humans and taken to Station 7 for the Space Security Service to research. A Slyther, Varga plant and the same magnedon the First Doctor came across was included. The Eleventh Doctor and Amy Pond arrived in the jungle area shortly before a Dalek force attacked while searching for a human experiment on Dalek nature which disgusted them. The jungle was destroyed along with the station when the Daleks concluded the experiment was not on board. (COMIC: The Only Good Dalek)
Behind the scenes
There is some dispute over the exact name of the place. The Doctor calls it "a petrified jungle" in Episode 1 and "the petrified jungle" in Episode 4, but calls it "the petrified forest" in Episode 7. It is called a "forest" by Alydon, Barbara, the Doctor and Ian, and a "jungle" by a Dalek, the Doctor, Ian and Susan. However, it is exclusively referred to as a forest in the novelisation. It is called "a petrified forest" in the novelisation of Remembrance of the Daleks and "the petrified forest" in the novelisation of The Evil of the Daleks. In The Only Good Dalek, it is called "the petrified jungle".