Public Release:  Redwood trees reveal history of West Coast rain, fog, ocean conditions

University of Washington

Many people use tree ring records to see into the past. But redwoods - the iconic trees that are the world's tallest living things - have so far proven too erratic in their growth patterns to help with reconstructing historic climate.


"This is really the first time that climate reconstruction has ever been done with redwoods," said Jim Johnstone, who recently completed a postdoctoral position at the UW-based Joint Institute for the Study of the Atmosphere and the Ocean. He is corresponding author of a study published online Oct. 24 in the Journal of Geophysical Research-Biogeosciences.

While coastal redwoods are not the longest-lived trees on the West Coast, they do contain unique information about their foggy surroundings. "Redwoods are restricted to a very narrow strip along the coastline," Johnstone said. "They're tied to the coastline, and they're sensitive to marine conditions, so they actually may tell you more about what's happening over the ocean than they do about what's happening over land."


Tree-ring research, or dendrochronology, typically involves a detailed look at a cross-section of a tree trunk. But the rings of a redwood are uneven and don't always fully encircle the tree, making it a poor candidate for anything except detecting historic fires. The new paper uses a painstaking approach that's more like processing ice cores. It uses the molecules captured in the wood to sample the atmosphere of the past.




"It's possible that the redwoods could give us direct indication of how that's worked over longer periods," Johnstone said. "This is just a piece that contributes to that understanding in a pretty unique place."




For more information, contact Johnstone at
