Although the quality of groundwater in our forests is better than 25 years ago, it is not yet fully satisfactory. The point emerges on Wednesday, from recent investigations by the Flemish Institute of Research for Countryside and Forests (known as “INBO”) in Brussels. Moreover, around a fifth of forest trees are diseased. Road traffic and agriculture are the main sources of pollution.
Whilst previously sulphur was the most damaging element in woods and forests, the largest problem which they now face is nitrogen, both in the form of ammonia and oxides of nitrogen (NOx). The quality of groundwater is thus one of the causes for the declining health of trees.
Moreover, a further long-term study by INBO shows that more than one in five trees in Flemish forests is not in a healthy condition. The situation is slightly better in Wallonia, although an exact comparison is difficult, given that the parameters differ between the regions.
Intensive livestock rearing is the main source of such pollution, alongside other agricultural activities. Such farms release large quantities of ammonia. Road traffic is a further significant polluting factor, since it is responsible for more than 60% of emissions of oxides of nitrogen.
Combined with global warming, air pollution moreover exerts high pressure upon Belgian woods and forests; these are often subject to insect infestations, as well as bacterial infections and fungi.
Arne Verstraeten, a doctoral student from INBO, concludes, “Urgent measures are necessary to combat the discharge of nitrogen emissions.” He goes on, “Belgium has one of the worst European records. The reason is partly due to Belgium’s population density, but also a lack of decisive policy-making.”