Task: Question Answering
Input (English): Passage: In the forest of Dapplewood, four "Furlings" – Abigail, a woodmouse; Edgar, a mole; Russell, a hedgehog, and Michelle, a badger – live alongside their teacher and Michelle's uncle, Cornelius. One day, the Furlings go on a trip through the forest with Cornelius, where they see a road for the first time. Russell is almost run over by Range Rover and the driver throws away a glass bottle that shatters in the middle of the road. Afterward, they go back to the forest to find that it has been destroyed by poison gas from an overturned tanker truck that blew a tire from the broken glass bottle. Michelle panics and runs to her home to find her parents, breathing in the gas and becoming severely ill. Abigail risks her own life and saves a comatose Michelle, but can do nothing for Michelle's parents. The Furlings go to Cornelius' house nearby for shelter after they find their homes deserted, believing everyone else to have succumbed to the gas. Cornelius tells the Furlings of his past encounter with humans that claimed the lives of his parents, hence why he is fearful of all human beings. He says he needs two herbs to save Michelle's life: lungwort and eyebright. With limited time, the Furlings head off for their journey the next day.
After facing numerous dangers, including a hungry barn owl, receiving aid from a flock of religious wrens led by preacher Phineas, and encountering intimidating construction equipment that the wrens call "yellow dragons", the Furlings make it to the meadow with the herbs they need. There, they meet the bully squirrel Waggs, and Willy, a tough but sensible mouse who grows a liking for Abigail. After getting the eyebright, they discover that the lungwort is on a giant cliff making it inaccessible by foot. Russell suggests they use Cornelius' airship, the Flapper-Wing-a-Ma-Thing, to get to the lungwort. 
Question: What do the Furlings discover has been destroyed by poison gas?
Output (English): forest of Dapplewood.