The scientists have two days to uncover some of the redwoods' best kept secrets inside the trees' canopy.
Redwoods are some of the most efficient carbon dioxide breathers and stores on the planet. So the trees help mitigate against climate change.
Friday, researchers took core samples, intending to study the trees' rings. That's a tall order -- some of the Muir Woods' redwoods are 1,000 years old.