Redwoods and Climate Change

Last week, while traveling in northern California, I had the opportunity to visit Redwood National and State Parks.  The trees there, coastal redwoods, are among the oldest and tallest on Earth.  Often called “living fossils”, they are currently facing the challenges of climate change.

Redwoods have an ancient heritage dating back more than 100 million years to the days of the dinosaurs. These giant trees once covered much of the northern hemisphere. Today, however, they are limited to a few distinct regions like the foggy coast of northern California.

These trees depend on coastal fog for water, especially during the dry summer season and in times of drought. Redwoods have countless tiny, closely spaced leaves that act like a comb to capture the moisture of the fog.   The condensed moisture then falls to the forest floor, watering the root system. Fog also helps to reduce transpiration, or the loss of water through leaf surfaces.

Fog along the northern California coastline is generated when cool, moist Pacific air interacts with warmer inland air. As ocean temperatures rise as a result of climate change, less fog is being created here.  In a recent study, scientists found that over the past one-hundred years coastal fog production has decreased by 33% in the region.

Given the species primeval lineage, coastal redwoods must have endured climate changes in the past.  This time, however, the change is happening very quickly and no one knows for sure how the tress will respond.   Scientists from the Redwoods and Climate Change Initiative have been studying core-samples from fallen trees to see how redwoods dealt with previous climate variations.  They have also been placing sensors on trees to measure temperature, humidity, rainfall, fog, and wind.  This data will, hopefully, help them discern the impacts of global warming on the unique redwood eco-system.

Redwoods in fog

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