Joshua Tree at risk due to increased pollution

Pollution from LA is increasing the levels of nitrogen in the soil in the inland desert. Desert plants are not equipped to deal with these higher concentrations, but the introduced grasses are. As a result, the grasses have a competitive advantage over the native plants. Increased grass growth, results in more tinder later in the season. This has resulted in more frequent and intense cycles of wildfires. The slow growing Joshua trees aren't able to adapt to the changing frequency of fires and are unable to re-establish themselves before the next fire sweeps through.