Study: Tree carbon storage may be less than previously thought
5 reported
A new study suggests trees may not store as much planet-heating carbon as hoped, finding that photosynthesis does not always lead to wood growth. Researchers examined 137 sites across the US and observed that trees stopped growing months before photosynthesis ceased for the year. The study’s lead author, Mukund Palat Rao, a carbon cycle scientist at Columbia University, stated that most models assume photosynthesis equals growth, but the findings show this is not the case. At eastern US sites, about 36% of yearly carbon uptake occurred after tree growth stopped in late summer, while in California it was about 26%. More detailed measurements at four sites indicated wood growth was limited to periods of low aridity and temperature, conditions becoming rarer due to rising global temperatures. The researchers warned that Earth system models may overestimate future forest carbon sequestration if they assume a tight link between photosynthesis and growth.
What’s reported
The study analyzed 137 sites across the US.
Trees stopped growing months before photosynthesis stopped.
At eastern US sites, 36% of yearly carbon uptake occurred after growth stopped; in California, it was 26%.
Wood growth was restricted to periods of low aridity and temperature.
The researchers said models assuming photosynthesis equals growth may overestimate future forest carbon storage.
Key figures
Mukund Palat Rao, carbon cycle scientist at the Lamont-Doherty Earth Observatory at Columbia University and lead author of the study.
Sources: The Guardian
