This Smithsonian article discusses why California’s Drought Killed Almost 150 Million Trees. The forests were too dense and temperatures were much higher than in previous droughts, exhausting water supplies and leading to mass die-offs.
The epic drought that began in the state of California in December 2011 and only officially ended in March of this year will have many lasting impacts—but one of the most severe is what it did to the trees in the central and southern Sierra Nevada mountains. A new study in the journal Nature Geosciences reports that by the drought’s peak, a combination of factors—including lack of rain, extreme heat and overcrowding stressed out the forest—lead to mass die-offs. In total, almost 150 million trees have died in California since the drought began.