UC Davis study: coast redwoods halt photosynthesis in extreme heat
The two-year study in Mendocino County is the first to document heat-stress shutdown in coast redwoods, a behavior seen in tropical trees.
A new study from researchers at the University of California, Davis found that coast redwood leaves dial down their photosynthesis during periods of extreme heat, according to Wired. The work is the first to examine how coast redwoods respond to heat stress of this kind, the researchers say.
The team drew on measurements taken twice a month for two years on coast redwoods in Mendocino County, near the southern part of the trees' range. During heat waves, the redwoods keep their stomata closed, which saves water but stops carbon intake and photosynthesis.
Similar behavior has been observed in tropical trees, the researchers note. Because the response halts carbon intake, the researchers say the effect could create a vicious cycle of carbon starvation that eventually kills trees.
For millennia, redwoods have anchored a stable ecosystem and can survive wildfires that devastate other tree species. Most redwoods in California and the Pacific Northwest nowadays are new-growth forests planted in the last couple of centuries.
Quick answers
What did the UC Davis study find about coast redwoods?
Researchers found that coast redwood leaves reduce photosynthesis during extreme heat, keeping their stomata closed. This saves water but stops carbon intake and photosynthesis.
How long did the redwood study last?
Measurements were taken twice a month for two years on coast redwoods in Mendocino County, near the southern part of their range.
Why could this heat response harm redwoods?
The researchers say the shutdown of carbon intake could create a vicious cycle of carbon starvation that eventually kills trees.