At the start of The Red Badge of Courage, what color did the landscape change to?

In the opening of the book, Crane writes that "the landscape turned from brown to green," meaning that winter is giving way to spring. What this means to the soldiers in the story is that the army is about to go on the campaign, as the muddy roads turn into "proper thoroughfares" that will allow for the movement of carts loaded with supplies and war material. Whether or not the army will begin a new campaign in the next few days becomes the subject of a heated debate between the men, as Henry listens. He is eager, in a sense, to be part of combat for the first time, but he is also fearful about how he will respond.