In the 1970s, red spruce was the forest equivalent of a canary in the coal mine, signaling that acid rain was damaging forests and that some species – especially red spruce – were particularly sensitive to this human induced damage. In the course of studying the lingering effects of acid rain, scientists came up with a surprising result – decades later, the canary is feeling much better.
Podden och tillhörande omslagsbild på den här sidan tillhör USDA Forest Service. Innehållet i podden är skapat av USDA Forest Service och inte av, eller tillsammans med, Poddtoppen.