The problem won’t fix itself in the near term, even though the era of acid rain is largely behind us. Our soils lost a lot of calcium (Ca) during the half century of acid rain. Today the rain is indeed much less acidic, but it is not a large Ca source. In fact, calcium input from rain and snow in Muskoka has actually fallen quite a bit as we have cleaned up pollution of the atmosphere. We need a source of Ca to replace that half tonne of Ca that was lost to acid rain, especially, compounding the problem, as we wish to continue harvesting trees in the region, removing their stored Ca from watersheds. The needed Ca must come either from us, or from nature, via long-term weathering of soil minerals. However, calcium-rich minerals were in low supply in Muskoka to start with, and they were the first to go during the acid rain era. What’s left will supply Ca very slowly as Muskoka rocks weather very slowly and produce little Ca when they do break down. Further, calcium-levels are now so low in our soils it will take a long time for these slow natural processes to rebuild soil Ca levels. If we want to fix the problem over the next few decades, we can’t rely on nature to do it for us. We created the problem, and we can fix it.
