Redwoods and Climate Change Initiative
We need to know how trees have responded to past climate change and also how they are responding today.

An ambitious program of applied science, conservation monitoring and research rooted in the coast redwoods and giant sequoias, this integrated Initiative will enable us to build a comprehensive understanding of redwood forest ecosystems from which we can make enlightened management recommendations for the future. The Initiative also promises to serve as a model for studying and protecting other ecosystems throughout California, the Pacific Northwest and the world.

Enabling this extraordinary team of scientists at this tipping point redwoods’ history is a rare opportunity to understand and protect the two iconic species that create Earth’s tallest forests. Nothing like this has been ever attempted, and now the need to study is urgent. No other team of investigators has the unique and complementary skills to conduct this integrated investigation of redwoods. The initiative will yield results that quantify redwoods’ vulnerabilities to climactic changes and their capabilities to mitigate these changes via photosynthesis, fog interception, wood production and carbon sequestration. The Initiative’s scientists are uniquely qualified, in part, because they have developed many of the methods to obtain the study’s data.

The Research Plots

Initiative Research Plots
Click to see Plot Photo Tours.

The scientists are installing 16 permanent one-hectare research plots throughout the geographic ranges of both California redwood species. They are combining tree and forest-level measurements with tree-ring data to calculate whole-tree and whole-forest rates of annual wood production back 1,000 years. These measurements will help the team predict tree and forest growth in response to changing climates.

Click on the map image (left) to view the interactive Plot Map and Plot Photo Tours. Note: At this time, not all plots have photos. We will continue to add new images as they come in from the field.

Mapping Tree and Forest Structure

Map of Tree and Forest Structure

Map: Robert Van Pelt.
Click to enlarge.

In each 1-hectare research plot, the science team will map tree and forest structure and measure above-ground carbon in logs, trees and other vegetation. The team also will monitor canopy and forest floor climatic conditions and use dendrochronology as well as regular remeasurements to quantify tree- and stand-level growth through time.

Back Through Millennia

Redwood Core Sample
Click to enlarge.

The structural measurements and annual growth rings also will enable accurate estimation of tree ages, the first available for tall standing redwoods. Analysis of the stable carbon and oxygen isotopes in the tree rings in state-of-the-art facilities will enable the team to reconstruct past climates and learn how redwoods respond to environmental conditions, including precipitation, temperature and humidity. These analyses will provide critical information on how redwoods throughout California are not only responding to current conditions but also how they have responded to climate over past millennia. Right now the team’s cross-dated dendrochronology record extends back over 1,000 years for both species. Additional sampling of fallen trees will enable extension of this amazing record back at least another 1,000 years.

Tall Harbingers

Map of Tree and Forest Structure
Click to enlarge.

With increasing height, treetops become increasingly sensitive to environmental conditions, and therefore the tallest redwoods may provide an early indication of climate change impacts. In addition to quantifying tree age, growth and structure, the research team is installing tree-top and ground-level microclimate monitoring systems to measure temperature, humidity, rain, snow, fog, light, wind and barometric pressure, which will enable real time monitoring of environmental conditions at each study site.

Mapping Tree Crowns

Redwood Greenhouse
Map: Stephen Sillett & Robert Van Pelt.
Click to enlarge.

The core science team will map tree crowns to quantify leaves, bark, wood and growth rates for whole trees, whole forests, and ultimately entire landscapes. These efforts allow the team to monitor tree and forest responses to environmental stresses and provide a powerful assessment of redwoods' capacity to store carbon in long-lasting, decay-resistant heartwood.

In the Greenhouse

Redwood Greenhouse
Photo by Anthony Ambrose.
Click to enlarge.

By manipulating temperature, carbon dioxide and water in greenhouse experiments, the scientists will examine how redwood seedlings and saplings from different parts of the two species’ ranges might react to climatic changes. They also will quantify carbon and oxygen isotopes in experimental trees in the greenhouse and compare responses to those evident in taller standing trees within the 16 research plots.

Sunlit canopy

Photo by Peter Buranzon.

Save the Redwoods League

For more than 90 years, Save the Redwoods League has been dedicated to protecting the ancient redwood forests so all generations can experience the inspiration and majesty of redwoods. In 1850, there were nearly 2 million acres of ancient coast redwood forests in California. Today, less than 5 percent remains and faces threats from unsustainable logging practices, poorly planned development and global climate change. Since its founding in 1918, the League has completed the purchase of more than 190,000 acres of land.

Save the Redwoods League
114 Sansome Street, Suite 1200
San Francisco, CA 94104

Phone: 415-362-2352