A similar observation was made at the Palmerton, PA superfund site. The nearby Blue Mountain was the recipient of toxic fumes spewed from a nearby tin processing plant for almost a century. The resultant depositions killed almost all the vegetation on the mountainside, which furthermore, did not decay because of the dearth of micro organism capable of living there.
"...concentrations of cadmium, lead, and zinc in the soil were so high as to prevent regeneration. In fact, metals levels stopped all microbial activity, creating a biological desert where trees that had been dead for 20 or more years could not decompose. "