Acid rain releases these fertilizers to be washed out of the soil, leaving the soil depleted of nutrients. But that is not the end of the problem. The tree roots provide sustenance to the mycorrhiza, and the mycorrhiza help the tree roots gather water and nutrients from the soil. But acid rain kills mycorrhiza, thus further reducing the ability of trees to absorb water and nutrients from the soil. But that is not all.
Acid rain kills off portions of the detritus food chain.
Furthermore, the litter promotes the growth of ferns, which give off substances that inhibit the growth of red spruce saplings, among others. This is not a complete description of problems caused by acid rain, but it gives a sense of the complexity of ecosystems, and how they can become unbalanced by thoughtless human intrusions. But one would be disappointed. Throughout the book, author Charles Little describes studies and statements by the U.S. Forest Service downplaying the importance of tree disease and death. Many scientists I talk to will not publicly say anything about the connection between air pollution and forest decline, but privately, to a person, they tell me, yes, we've got a problem.