Climate Change May Push Redwood Decline

According to a new report, climate change may be thinning San Francisco's coastal fog and threatening giant redwoods.

"Fog prevents water loss from redwoods in summer, and is really important for both the tree and the forest," said biologist Todd Dawson of the University of California Berkeley. "If the fog is gone, we might not have the redwood forests we do now."

The affected trees are known for their long lifespan and great size, but fog decrease could lead to declining tree populations as members of the species move elsewhere for cooler temperatures and greater humidity.

Data going back to 1951 indicated that "coastal fog has decreased in connection with a decline in the coast-inland temperature gradient and weakening of the summer temperature inversion," according to Berkeley's James Johnstone, the leader of the study.

"Fog is clearly a dominant climatic factor on the California coast, and long-term reductions likely have and may continue to impact the water and carbon economy of redwoods and other coastal endemic species," concluded the report, published in the Proceedings of the National Academy of Sciences.