Heat Waves Altered Redwood Tree Growth
University of California Davis researchers found that extreme heat disrupts photosynthesis in coast redwoods.
Updated on Oct. 6, 2026 in Botany
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Researchers at the University of California Davis discovered that coast redwood trees reduce photosynthesis during periods of extreme heat to conserve water. By closing their stomata, the trees avoid water loss but also stop taking in the carbon dioxide required for growth.
Why it matters
The findings suggest that intensifying heat waves may limit the growth of these iconic trees and reduce their overall ability to sequester carbon. This shift could have significant implications for the long-term health and stature of redwood forests across California.
Researchers measured photosynthesis in individual leaves twice a month over a two-year study period. The data shows that redwoods typically function best between 8 and 27 degrees Celsius before heat stress necessitates the closure of stomata.
The players
University of California Davis
This public research university conducted the multi-year study on the physiological impacts of heat stress on coastal redwoods.
The details
Using specialized instruments to monitor individual leaves, researchers observed that redwoods close their stomata to prevent excessive water loss when temperatures exceed their ideal range. While the trees maintained their capacity to photosynthesize after heat waves subsided, the energy loss during periods of stress threatens to impact their height and carbon sequestration potential.
Timeline
1974: A tree-trimmer discovered a marbled murrelet nest 150 feet above the ground.
Two-year study period: Researchers conducted bi-monthly measurements of redwood photosynthesis.
In 5 or 10 years: Experts anticipate potential increases in the frequency and intensity of heat waves.
The Big Picture
This study updates the understanding of forest resilience by identifying the biological mechanism behind carbon starvation in redwoods. The findings follow a pattern set by the University of California Davis coast redwood heat stress study, which quantifies how atmospheric changes directly impact forest physiology.
The potential loss of carbon sequestration capacity from these forests could accelerate long-term climate changes affecting local ecosystems. Future forest management policies may need to adapt to account for the reduced growth potential of redwoods as extreme heat events become more common.
The takeaway
While coast redwoods demonstrate a resilience by retaining their ability to photosynthesize after stress, the cumulative energy loss poses a threat to their historical growth rates. Residents and conservationists should monitor local forest health metrics as climate projections indicate more frequent heat events.
Further reading
For more on the unique environmental requirements of native species, explore our Botany coverage.
Source note: This article includes information reported by Vox.
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