can anyone tell me why is forest called lifeline?

because forests consists of many  trees which help us to get oxygen(the life giving gas) and absosb carbon dioxide( the gas required for photosynthesis) which give us food and water and plants also purify the dirty air or the air which is not suitable for us to breathe and provide us amny things like wood, coal, food and many else things.

hope u wil get all these answers