However, acid deposition has accelerated the leaching of plant nutrients from soils in some areas, which has hindered tree growth, as researchers found in the on-going Hubbard Brook studies (see Science Focus, above, and the Chapter 2 Core Case Study, p. 28). Scientists estimate that an additional 80% reduction in SO2 emissions from coal-burning power and industrial
plants in the midwestern United States will be needed before northeastern lakes, forests, and streams can recover from past and projected effects of acid deposition.