On the edge: Eastern redwoods

Second-growth coast redwoods at Las Posadas State Forest
Second-growth coast redwoods at Las Posadas State Forest

I recently drove eastward through the many vineyards of the Napa Valley in search of coast redwoods living on the species’ eastern boundary. Given how widespread redwoods used to be on planet Earth, the edges of the natural redwood range today are quite intriguing.  Are we looking at a retreating edge where the redwood forest is slowly contracting towards the coast? If so, will redwoods still last in Napa County for generations to come?

My eastern redwood expedition took me to Las Posadas State Forest, a protected forest managed by CALFIRE, to see whether the redwoods there would provide a prime opportunity for us to study the habitat limit for coast redwoods. As I stumbled through the mixed oak forest on the property, I suddenly dropped down into a creek drainage where the redwoods were pushing skyward.

Century-old redwoods on the eastern edge of the species' range
Century-old redwoods on the eastern edge of the species’ range

I expected to find a dry, stunted redwood forest here since summers can be so hot in Napa without the frequent cooling influence of fog.  However, undeniably this was a coast redwood forest not unlike the kind I typically find in Marin and Santa Cruz Counties. Bay laurel trees and green ferns grew in the redwood shadows along the creek. Remarkably these redwoods were cut in the early part of the 1900s, but this forest has regrown and appears to be thriving. This redwood forest may be on the eastern edge, but at first look I didn’t see signs of stress in the forest. Of course not everything is visible on the surface and makes me think we should look more deeply! I’d love to look at the tree rings in these redwoods and see how these amazing trees have been coping with the Napa climate.

For more on how we study climate impacts on redwoods throughout the state, learn about our Redwoods and Climate Change Initiative.

About the author

Emily Burns, the League’s former Director of Science, led the research program that includes the Redwoods and Climate Change Initiative. She holds a PhD in Integrative Biology on the impacts of fog on coast redwood forest flora from the University of California, Berkeley.

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