Coastal redwoods at Big Basin State Park, California

Between Editorial Board meetings and guest seminars in Los Angeles, Stanford and Berkeley last week, I met up with Todd Dawson from Berkeley, who has dedicated his career to understanding the ecophysiology of California redwood. We spent a day with some of his team (and also Jeff Chambers from the Lawrence Berkeley National Lab) and visited their research plots in Big Basin State Park, 1-2 hours south of San Francisco. The forest standards here are dominated by magnificent coastal redwoods (Sequoia sempervirens).  It is an evergreen, long-lived  tree living 1,200–1,800 years or more. This species includes the tallest living trees on Earth, reaching up to 115.5 m in height (without the roots) and up to 26 feet (7.9 m) in diameter at breast height (the largest trees in terms of mass are its close relative the giant sequoia - Sequoiadendron giganteum, 

This year California has experienced its strongest drought for over a century, and these are exceptionally stressed and losing leaves. This may be a long-term adaptive strategy to drought (they may regain leaves next year and are simply reducing their water demand to get through this period of drought) or maybe a sign of environmental conditions passing a critical threshold.