Forested areas readily attract clouds and rain, and trees also grow upwards, so their foliage takes the brunt of the rainfall. But rain also soaks into the topsoil and drains into lakes, producing "acid soil" and "acid lakes."
若由雨水降落的行程來看，森林區易聚雲雨，加上樹木往上伸展，本來就是前鋒部隊，首當其衝，但雨水接下來再流向地表、土壤、湖泊… …，「酸土」、「酸湖」便接著出現了。