Acid rain is rainfall that has a very low pH level, which is on the acidic side of the scale. It contains acidic deposits that are potentially harmful and damaging to the ecosystem. Forests are one of the areas where the effects of acid rain are readily seen. The Black Forest in Germany is one area that has seen an effect from acid rain.


Loss of Leaves and Needles

The trees in Germany's Black Forest initially showed a loss of leaves and needles. According to the Upper Midwest Aerospace Consortium, or UMAC, scientists first noticed the declining leaves in the Black Forest in the 1960s. The trees began losing as much as 25 per cent of their leaves and needles when compared to previous years. This is one of the most easily observed effects. By 1990, around half of the trees in the forest showed this disturbing trend.

  • The trees in Germany's Black Forest initially showed a loss of leaves and needles.

Damage to Root Systems

The heavy-metal deposits of acid rain result in damage to tree root systems. This damage is primarily caused by the high levels of aluminium in the soil, which harms the root hairs of the tree and minimises nutrient uptake from the soil. Gradually, the tree roots diminish until they are not efficient.


Seedling Mortality

The acid rain damaging the trees in the Black Forest has a pronounced effect on seedlings in the forest. Though younger trees have less exposure to acid rain, they are also more likely to experience negative effects from the highly acidic soil conditions and the rain itself. Seedling mortality rates increase as a result of acid rain in the forest, with fewer trees surviving the harsh conditions.


Death of Trees

The Germans named the death of the trees in the Black Forest "Waldsterben," meaning "tree death." The appearance of the trees in the forest became so bare of needles and unhealthy that the trees started to look dead and blackened. The only potential cause of the final death of the trees was acid rain, as no other causes were found by scientists.