SAN FRANCISCO (AP) — Scientists climbed high into old-growth redwoods in the San Francisco Bay Area as part of a two-day effort to gather data and document the different creatures that live in the tree canopy.

About 300 volunteer scientists on Friday began documenting the bugs, birds, mosses, plants and other living organisms that call the trees and federal lands in the area home.

The researchers are measuring the trees from top to bottom in an effort to determine the redwood forest’s ability to sequester carbon, said Stephen Sillett, a Humboldt State University professor and leading redwood scientist.

“We are trying to figure out the biomass of the redwood forest, what is its capacity to sequester carbon ... and relate its performance over the last century to previous periods,” Sillett said.

Redwood tree rings go back to the year 328, providing a valuable resource for understanding previous periods of drought and other climatic changes.

By studying the rings of many trees, scientists hope to be able to understand how the trees will react to the earth’s warming temperatures.

The convergence of scientists is part of a two-day event called BioBlitz, an event sponsored by the National Park Service and National Geographic that seeks to get young people interested in science.

Volunteers are gathering in Muir Woods and other areas of the Golden Gate National Recreation Area to gather tree data and participate in other projects, including an insect-identification effort in San Francisco’s Presidio.

“There are over 500 families of insects in California and somewhere in the order of 25,000 individual species of beetles alone,” University of California, Davis forensic entomologist Robert Kimsey said. “There is a hell of a lot out there right now that we just don’t know about yet.”