Forests, lakes, and streams: Acid rain can cause widespread damage to trees. This is especially true of trees at high elevations in various regions of the U.S. Acidic deposition can damage leaves and also deplete nutrients in forest soils and in trees so that trees become more vulnerable to disease and environmental stress.
When lakes and streams become more acidic than normal, they cannot continue to support the same types of fish and aquatic life as in the past. Fish communities dwindle due to high mortality, a reduced growth rate, skeletal deformities, and failed reproduction. Lakes ultimately become home only to species that can tolerate high-acid conditions. Game fish, such as trout, are particularly sensitive to acidic water conditions.
A healthy lake has a pH of 6.5 or higher. Only a few fish species can survive at a pH of below 5; at a pH of 4, the lake is considered dead. A decrease in fish populations is often the first sign of an acidification problem.