Hubbard Brook Experimental Forest (IMAGE) Cary Institute of Ecosystem Studies Caption The acidity of precipitation falling on the Hubbard Brook Experimental Forest in New Hampshire has decreased by about 80% since 1970. Credit Photo: Jordan Jessop) Usage Restrictions To promote this press release. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.