In summer, the thick stands of grass turn brown and brittle, creating a vast fuel reserve for wildfires, she said. This means a fire will burn very hot, potentially too hot for the survival of native seeds, he said. Native plants have evolved to withstand and thrive only certain temperatures of wildfires. The exotic grasses change all this, he said. The East Coast is where you hear so much about acid rain, said Mark Fenn, a plant pathologist at the USDA who has been working with Allen.
Acid rain refers to rain or snow that contains heavy concentrations of sulfuric and nitric acids.
Acid rain is formed by the burning of fossil fuels, especially coal, which is high in sulfur. El Nino may be the solution to soil contamination, researchers say, because the heavy rains generated by the warm-water weather phenomenon dissolve the nitrogen compounds and flush them out of the soils. But this, too, has problems, Fenn said. What comes out of our tailpipes goes into the atmosphere and falls on the surface of the forest. When it rains, the water transports the nitrogen's into ground water and streams.