After taking a close new look into soil chemistry and where calcium comes from, scientists said that acid rain may be doing less damage to forests than anticipated. In a report published in Nature, researchers said some trees, especially spruce and firs, cooperate with soil fungi to dissolve calcium directly from a mineral called apatite. This alternate source of calcium may account for what has been seen as excess calcium that scientists see leaving the forests via streams. These new findings should improve their understanding of what happens to forests that live downwind from the huge power plants that produce acid rain.