carbon fixation by old trees

Carbon fixation by older trees; the more the older!

Rate of tree carbon accumulation increases continuously with tree size.

Most living things reach a certain age and then stop growing – male
elephants are an exception, by the way – but trees accelerate their
growth as they get older and bigger, a global study has found.
The findings, reported by an international team of 38 researchers in the
journal Nature , overturn the assumption that old trees are less
productive. It could have important implications for the way that forests
are managed to absorb carbon from the atmosphere.
“This finding contradicts the usual assumption that tree growth
weventually declines as trees get older and bigger,” said Nate
Stephenson, the study’s lead author and a forest ecologist with the US
Geological Survey (USGS). “It also means that big, old trees are better
at absorbing carbon from the atmosphere than has been commonly

The scientists from 16 countries studied measurements of 673,046 trees
of more than 400 species growing on six continents, and found that
large, old trees actively fix large amounts of carbon compared to smaller
trees. A single big tree can add the same amount of carbon to the forest
in a year as is contained in an entire mid-sized tree, they found.

Reference: more-older-carbon