The ongoing problem of acid rain causes injury, slow growth, or sometimes death of trees. Some soils are able to buffer the acidity effectively. Other soils, however, lack an effective buffering capacity, putting trees at risk.
How acid rain damages trees
While acid rain can directly damage leaves, it also shifts soil pH, making soil nutrients unavailable to plants. Acid rain can also release the aluminum in soil. Trees are then able to take up the aluminum, which is toxic to them.
Trees in alpine regions are more at risk, even if they have buffering soil. The clouds that bathe the mountain tops are acidic, subjecting the trees to more acidity than trees at lower elevations.
A ray of hope, please.
As has been shown in research done by Cornell University, mycorrhizal fungi can help to protect some trees from the effects of acid rain.
Through the hyphal network of mycorrhizal fungi, the trees has access to a greater amount of calcium — a nutrient made less available by acid rain. Unfortunately, not every tree will form associations with mycorrhizae, leaving those trees most vulnerable.
Additionally, mycorrhizae will not prevent acid rain from leaching toxic aluminum out of the soil.
What can I do to help?
Calcium amendments to your soil will help to make the nutrient more available for trees. Bone meal, powdered eggshells, or powdered oyster shells can help to boost the calcium available to trees.