TREES - Red cedar trees rebounded after Clean Air Act

A species of old trees in the Appalachian Mountains is growing faster than expected in the wake of clean-air controls implemented decades ago, a new study shows. The research on eastern red cedar trees — all between 120 and 500 years old — also showed changes in the types of carbon and sulfur in their tree rings a few years after the Clean Air Act was enacted in 1970.

http://www.nbcnews.com/science/red-cedar-trees-rebounded-after-clean-a