Quote from SpinBuilder
in an update a couple months ago, Biomes were added, and with that, a tinting system for the grass and leaves. they are greyed out on the terrain.png and are then tinted ingame. the grass is the grey texture on the top left. the leaves are the two grey "leaf looking things" at the top-left-middle. don't worry, your not the first to ask this.
thanks this helped me heaps