Groundwater quality under forests in the Netherlands, 1990 and 2000
Groundwater quality under forests has improved considerably in the last ten years. Nevertheless, acid levels are still too high in uppermost groundwater in 30% of the forest area.
Groundwater under forests much better
The fall in the deposition of SOx, NOy and NHX has resulted in a considerable improvement in groundwater quality under forests in the last ten years. The average concentrations of nitrate, sulphur and aluminium in the uppermost groundwater under forests in sandy areas have fallen. The area of forest on sand where the desired quality standard for nitrate (25 mg/l) in the uppermost groundwater is exceeded has fallen from 50 to 30%. The average Al/Ca ratio in the roots zone, a measure for acidification, has fallen by half since 1990, indicating an improvement in the root environment.
Positive effects of acidification policy
The policy for reducing emissions of potentially acid substances is bearing fruit. Nitrogen emissions and deposits must, however, continue to fall in order to bring the acidification and eutrophication of forests to a complete halt.
Acidification and eutrophication result in changes in vegetation in nature reserves.
