Vermont Forest Indicators Dashboard

Precipitation Acidity

Score for 2018:
Long-Term Trend:
Scores are 
Acid rain was first noted as a threat to forests in the mid 20th century1. Acid rain harms forests by physically damaging leaves and roots, as well as leaching important nutrients from soils. Some species such as red spruce (Picea rubens) and sugar maple (Acer saccharum) are particularly sensitive to acid rain, causing observed long-term decline. Due to these declines, the Clean Air Act and subsequent amendments were enacted; since then, there has been a steady increase in the acidity of rain. Here, acid deposition is assessed as the mean annual pH of precipitation in Underhill, VT.The pH scale runs from zero to 14, 7 being neutral. The pH lower than 7 is acid and higher than 7 is base. Note that normal, unpolluted rainfall has a pH of about 5.6 on this logarithmic scale. The current year is scored as the distance between the minimum and maximum values.
1Likens, G.E., Wright, R.F., Galloway, J.N. and Butler, T.J., 1979. Acid rain. Scientific American, 241(4), pp.43-51.
FEMC Archive Resources
Dataset: 1984 to Current NTN Annual Data for Vermont